North American Fungi

Volume 5, Number 1, Pages 1-107 Published February 19, 2010

Pluteus section Celluloderma in the U.S.A.

Andrew M. Minnis1 and Walter J. Sundberg2

1Systematic Mycology & Microbiology Laboratory, USDA-ARS, B011A, 10300 Baltimore Ave., Beltsville, MD 20705, U.S.A. 2107 Cardinal Dr., Murphysboro, IL 62966-5255, U.S.A.

Minnis, A. M., and W. J. Sundberg. 2010. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1): 1-107. doi: 10.2509/naf2010.005.001 Corresponding author: A. M. Minnis, [email protected]. Accepted for publication November 30, 2009. http://pnwfungi.org Copyright © 2010 Pacific Northwest Fungi Project. All rights reserved.

Abstract: Pluteus is a cosmopolitan euagaric genus found commonly on xyloid (woody) substrates. A taxonomic revision is presented for species of Pluteus section Celluloderma known from the U.S.A. Type studies of all taxa originally described from the U.S.A. as well as additional morphological data and keys are presented. Two new species, Pluteus deceptivus and Pluteus phaeocyanopus, and one new variety, Pluteus seticeps var. cystidiosus, are described, and the new name, Pluteus homolae, is given for Prunulus ludovicianus. Notes are provided for two extralimital taxa and three taxa that are doubtful or excluded from Pluteus section Celluloderma.

Key words: Agaricales, Agaricomycetes, Basidiomycota, Celluloderma, lectotype, Pluteaceae. 2 Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107

Introduction: The family Pluteaceae Kotl. & (ranging from a cutis to trichoderm to loosely Pouzar is characterized in part by free lamellae, arranged hymeniderm with all elements having a convergent (inverse) lamellar trama, and Q greater than 3). Section Pluteus typically has a inamyloid, cyanophilic basidiospores that are pileipellis with a cutis and thick-walled pinkish to brownish pink in mass (Stuntz 1977, pleurocystidia while section Hispidoderma has Singer 1986). The three genera of agarics some form of filamentous pileipellis and thin- included in the Pluteaceae are Pluteus Fr. walled pleurocystidia (Singer 1986, Vellinga (usually without both annulus and volva), 1990). Section Celluloderma is defined by a Volvariella Speg. (with volva but without cystoderm (cellular) pileipellis composed of annulus), and Chamaeota (W.G. Sm.) Earle (with ellipsoid to saccate-pyriform to vesiculose cells annulus but without volva) (Singer 1986, Minnis with or without cystidioid elements (Homola et al. 2006). Some Chamaeota species have been 1969, 1972; Singer 1986). Smith and Stuntz transferred into Pluteus (Minnis et al. 2006, (1958) were of the opinion that all of the Corriol and Moreau 2007) when it was shown pileipellis elements were of homologous origin that the presence of an annulus was not and that there was no need to distinguish a delimitating at the generic rank in those taxa. It separate class called dermatocystidia. Hence, we is possible that the remaining Chamaeota species prefer cystidioid elements as a generic term to will be incorporated into Pluteus in the future. A indicate homologous morphological variation in fourth monotypic genus typified by Brauniella the pileipellis elements to dermatocystidia. alba (Rick) Rick ex Singer is a poorly known secotioid fungus from South America that also Section Celluloderma has been divided into has been considered to be part of the Pluteaceae various subsections by different authors. Singer (Singer 1963). (1958) recognized subsections Mixtini Singer and Eucellulodermini Singer, which are characterized Species of Pluteus are commonly found growing by the presence of cystidioid elements in the on xyloid (woody) substrates including stumps, pileipellis in the former and the lack of these logs, fallen branches, woody debris such as elements in the latter. Vellinga and Schreurs sawdust, and buried wood (Orton 1986, Singer (1985) divided section Celluloderma into 1986). These organisms are saprotrophic and subsection Mixtini, subsection Hispidodermini presumably never mycorrhizal (Orton 1986). (Fayod) Vellinga & Schreurs, and subsection However, the type of rot is not known for certain Eucellulodermini. In their system of since it is unknown if they can degrade lignin classification, subsection Mixtini contained and/or cellulose. There is a lack of tissue culture species with two different types of pileipellis work with Pluteus because of isolation problems elements including cylindrical to fusiform and the relative inability of researchers to initiate elements and sphaeropedunculate to clavate basidiospore germination (Banerjee and elements; subsection Hispidodermini was Sundberg 1991, 1993b; Banerjee 1992). As a characterized by cylindrical to fusiform elements result, information on mating behavior and in an anticlinal arrangement; and subsection biological species concepts in Pluteus is lacking Eucellulodermini exhibited sphaeropedunculate (Banerjee 1992). to clavate elements (Vellinga and Schreurs 1985). Homola (1969, 1972) correctly used Pluteus Three sections are widely accepted in Pluteus subsection Celluloderma, an autonym, as a including sections Pluteus, Hispidoderma Fayod, replacement for Pluteus subsection and Celluloderma Fayod (Singer 1986). The first Eucellulodermini in accordance to the two sections possess filamentous pileipelli International Rules of Botanical Nomenclature at Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 3 that time. However, the rules subsequently synonymy. Unfortunately, supporting changed (McNeill et al. 2006), and Pluteus illustrations were not printed in the final work subsection Eucellulodermini is now correct. (Smith and Stuntz 1958). These illustrations were not found at the University of Michigan Murrill (1917) published the first major (Patricia Rogers, personal communication), the taxonomic treatment of Pluteus, which included University of Washington (Joseph Ammirati, all of the species known from North America at personal communication), or in Smith’s materials that time. Murrill (1917) included several species possessed by Nancy Smith Weber (personal described previously from the U.S.A. and several communication) and are likely lost. The new ones. Unfortunately, the protologues for the conflicting data presented by Singer (1956) and new species were quite short and often lacked Smith and Stuntz (1958) created additional enough information for species delineation. confusion about the identity of Pluteus species Additionally, no data regarding the anatomical found in the U.S.A. structure of pileipelli that would allow for classification into the major sections of Pluteus Banerjee and Sundberg (1993a) re-examined were offered in Murrill’s (1917) work. Some numerous type collections housed at the New workers discussed below have re-examined the York Botanical Garden. They provided new available type specimens of Murrill (1917) with micromorphological data, illustrations, sectional hopes of elucidating where the species should be classifications, and opinions on synonymy. classified and how to identify them. Singer Banerjee and Sundberg (1993a) also studied (1956) made a significant contribution towards a some Pluteus type specimens not seen by world monograph of Pluteus. He included previous workers. This work clarified some of the information about several type specimens, conflicting data from Singer (1956) and Smith opinions on synonymy, descriptions of numerous and Stuntz (1958), but it left several taxonomic new taxa, and classified species into sections. questions without definitive answers as a Singer’s work did not provide microscopic data comprehensive approach to section Celluloderma on some taxa, lacked illustrations for some was not employed since the authors were species, and did not include all previously focusing on section Pluteus during that time. described taxa from the U.S.A. Several subsequent Singer publications (1958, 1959, 1961, Homola (1972) made the only major contribution 1973, 1977, 1989) among others clarified and towards a monograph of Pluteus section added to the understanding of Pluteus taxa in the Celluloderma in the U.S.A. This work is U.S.A. frequently cited and has served as a standard for these taxa in North America. However, quality Smith and Stuntz (1958) provided the next major illustrations of described microscopic characters examination of Pluteus type collections from the for many Pluteus species found in Homola’s U.S.A. They discussed the importance of Pluteus dissertation (1969) were not published, and type collections, the importance of experience several North American species were not with fresh specimens and general skills needed included in Homola (1972). In addition, about for the study of types, and the concern that some half of the species included in the monograph types were mixed collections or misplaced were characterized by the author as imperfectly specimens in the wrong packages. They also known (Homola 1972). One factor contributing noted several discrepancies between their work to this lack of knowledge was Homola’s exclusion and that of Singer (1956). Smith and Stuntz of several type collections from the scope of his (1958) included quality descriptions with enough research. The uncertainty about these taxa led to data for sectional classification and opinions on the creation of a key that is at best difficult to use. 4 Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107

All of these factors made it challenging to identify (1978). These are abbreviated R, M & P, and M in North American species of Pluteus section the text. Color terms from these references are Celluloderma with any degree of confidence. included in parentheses. Maerz and Paul (1950) Currently, no acceptable comprehensive and Kornerup and Wanscher (1978) citations identification key to Pluteus section include a three character reference to the color Celluloderma in the U.S.A. exists. plate that more or less matches the specimen. Other color terms are not presented in The purpose of the present study is to enhance parentheses. Spore print color was noted, but the knowledge of Pluteus section Celluloderma in standard color terminology was not employed the U.S.A., primarily through morphological due to the variability in color discussed by examinations of Pluteus materials including type Homola (1969). specimens. A comprehensive survey of herbarium specimens including type speciems Standard techniques were employed to study was undertaken and field collections were made microscopic characters of examined specimens to supplement existing data. Descriptions of taxa (Smith 1949, Largent et al. 1977, Singer 1986). were made and identification keys for Pluteus Small pieces for sectioning were cut from dried section Celluloderma were developed. These herbarium material, wetted in 95% ethanol for 1 keys help to distinguish taxa and serve as a guide min, and rehydrated for at least 1 min in distilled to a better understanding of what features are water. The pieces were subsequently blotted dry important for identification of species in Pluteus with a paper towel and hand sectioned with a section Celluloderma in the field and the lab. razor blade. Sectioned material was then Undoubtedly, much more work with a variety of mounted in 3% KOH for microscopic viewing. techniques needs to be done with cooperation Amyloid reactions were studied with Melzer’s between taxonomists on different continents to reagent (Largent et al. 1977). All anatomical determine if morphologically similar taxa from features were inamyloid in Melzer’s reagent, and different regions are conspecific or distinct, and materials that were tested are indicated with Mi. new Pluteus taxa will surely be discovered in the future. Because of the minute nature of many basidiocarps of Pluteus section Celluloderma, Materials and Methods less destructive sampling methods were often Field collections were made and examined using used for nearly all observations and standard methods for agarics (Smith 1949, measurements. These methods are similar to the Largent 1973, Singer 1986). Numerous herbaria squash technique utilized by Homola (1969). were surveyed for existing collections and loans were obtained from those that had significant All measurements of basidiospores are from specimens of interest. Herbarium acronyms are hymenial tissues. Homola (1969) found no those of Holmgren and Holmgren (1998). statistical difference between basidiospores from spore prints and those from hymenial tissues in Color terminology of cited descriptions are those his examination of Pluteus materials. For non- of the original authors. Other color terms are type specimens, a minimum of 15 or 20 taken directly from notes associated with the basidiospores were measured. For type examined specimens. Standard color specimens, at least 30 basidiospores were terminology from color references were used to measured. Length to width ratios are reported as take notes on fresh specimens and rarely, dried Q. Mean values for length, width, and Q are specimens. These include Ridgway (1912), Maerz designated as Lm, Wm, and Qm, respectively. For and Paul (1950), and Kornerup and Wanscher all other anatomical characters including Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 5 pleurocystidia, cheilocystidia, caulocystidia, order of the text was modified to match the basidia, cuticular elements, and hyphal diameter format of this manuscript, but the words of various basidiocarp tissues, at least ten themselves were not modified. Also, metric units structures were measured. The length of the are given in parentheses. For some species, sterigmata was not included in the measurements several relevant type collections were studied. In of the basidia. most instances descriptions are separated according to species name and the class of type Illustrations: Numerous figures depicting specimen. This was done to ensure that data for micromorphological characters are presented in different type collections could be clearly this study. These were constructed from digital separated. In previous studies, type data was images of examined materials. Slide presented collectively with data from other type preparations were first observed with a Leitz and/or non-type collections. This leads to binocular, bright field microscope. considerable confusion when the nature of the Representative structures of interest were then type specimen is being considered and this photographed with a Nikon CoolPix 4500 digital protocol attempts to avoid this problem. General camera (Nikon Corporation, Tokyo, Japan) descriptions include data on non-type specimens attached to the camera tube of the microscope via and are kept separate for the same reason. Zarf's Microscope Lens Adapter for Nikon CoolPix, LNS-23D© (Zarf Enterprises, Spokane, Terminology of morphological characters follows WA). Line drawings of these structures were Largent (1973), Largent et al. (1977), and Vellinga subsequently made with Adobe® Illustrator® CS2 (1988, 1990) with a special emphasis on the (Adobe Systems Incorporated, San Jose, CA). Vellinga works for microscopic characters, Scale bars were similarly made from digital especially basidiospores. Although an attempt images of a stage micrometer photographed at has been made to be as precise as possible with the same magnification and camera settings as terminology, cystidial shapes are frequently the photographs of illustrated variable within and among species of Pluteus. micromorphological characters. Thus, terms such as lageniform and utriform may in general be thought of as variable and Species descriptions: Abbreviations for variations of fusoid-ventricose. authorities are taken from the online version of the Authors of Fungal Names at the Index Results Fungorum website Keys to the sections and subsections are (http://indexfungorum.org/Names/AuthorsOfFu accompanied by an abbreviated nomenclatural ngalNames.asp). For precision, all of the authors treatment for each of these taxa. Synonyms for associated with a taxon name are cited in these taxa and citations for the type specimens nomenclators. Journal citations in nomenclators, are not included. Interested readers are referred whenever possible, follow Lawrence et al. (1968) to studies by Singer (1958, 1986) and Vellinga and Bridson and Smith (1991). The taxa are and Schreurs (1985). For this study of section treated alphabetically. Celluloderma, the classification system of Singer (1986) is utilized. Species with a filamentous Type studies are included here with both pileipellis classified in section Celluloderma macroscopic and microscopic data. In some subsection Hispidodermini by Vellinga and cases, the macroscopic description that is Schreurs (1985) are excluded because this presented was modified from the protologue, and subsection may be a distinct section, section in these cases, the original works are cited later in Hispidoderma. Banerjee (1992), Banerjee and the species descriptions. In these instances, the Sundberg (1993a), Citérin and Eyssartier (1998), 6 Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 and Rodríguez and Guzmán-Dávalos (2001) filamentous pileipellis and thin-walled apparently agree with this assessment as they did pleurocystidia are distinctive. not adopt the Vellinga and Schreurs (1985) classification system. Pluteus section Pluteus Type species: Pluteus cervinus (Schaeff.) The Genus Pluteus P. Kumm. Diagnostic characters: Pluteus Fr., Floram Scanicam: 338. 1835. Microscopically, the combination of a Type species: Pluteus cervinus (Schaeff.) filamentous pileipellis and metuloid (thick- P. Kumm. walled) pleurocystidia are definitive for this Diagnostic characters: section. Macroscopically, lamellae free, partial veil present or absent, universal veil with well- Key to Subsections of Pluteus section developed volva absent, spore print pinkish to Celluloderma found in the U.S.A. brownish pink. Microscopically, lamellar trama convergent. 1. Cylindrical to fusiform (cystidioid) elements intermixed with cellular shaped elements in Key to Sections of Pluteus found in the pileipellis (mixed U.S.A. cystoderm)…………………...……..subsection Mixtini 1. Cylindrical to fusiform elements rare or lacking 1. Pileipellis composed of filamentous elements in pileipellis, cellular shaped elements forming a cutis, trichoderm, or loosely arranged predominate………....subsection Eucellulodermini hymeniderm with all elements having Q greater than 3………………………………..………….………………2 Pluteus subsection Mixtini Singer, Lloydia 1. Pileipellis a cystoderm (at least some with 21: 257. 1959 (1958). cellular shape)…………….…...section Celluloderma Type species: Pluteus psichriophorus 2. Pleurocystidia thin-walled……………………………. (Berk. & Broome) Sacc. (as Pluteus ……………………………………..section Hispidoderma psychriophorus) 2. Pleurocystidia thick-walled..…...section Pluteus Diagnostic characters: Microscopically, the presence of cylindrical to Pluteus section Celluloderma Fayod, Ann. fusiform and globose, ellipsoid, pyriform, clavate Sci. Nat. (Paris) 9: 364. 1889. to sphaeropedunculate elements in the pileipellis Type species: Pluteus nanus (Pers. : Fr.) is distinctive. P. Kumm. Diagnostic characters: Pluteus subsection Eucellulodermini Microscopically, at least a percentage of the cells Singer, Lloydia 21: 274. 1959 (1958). of the pileipellis are globose, ellipsoid, pyriform, Type species: Pluteus nanus (Pers. : Fr.) clavate to sphaeropedunculate in shape (cellular). P. Kumm. Diagnostic characters: Pluteus section Hispidoderma Fayod, Ann. Microscopically, the absence of a significant Sci. Nat. (Paris) 9: 364. 1889. number of cylindrical to fusiform elements in the Type species: Pluteus leoninus (Schaeff. : pileipellis is definitive. Fr.) P. Kumm. Diagnostic characters: Key to Pluteus subsection Mixtini species Microscopically, the combination of a found in the U.S.A. Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 7

1. Lamellar edges darkly 8. Pleurocystidia frequently somewhat broadly pigmented...... ……..………(1) P. eugraptus lageniform to utriform, hyaline….(8) P. cyanopus 1. Lamellar edges concolorous with faces …………2 8. Pleurocystidia frequently narrowly lageniform, 2. Some cheilocystidia rostrate....(2) P. thomsonii many brown pigmented…..(15) P. phaeocyanopus 2. Cheilocystidia not rostrate………….……….……...3 9. Pileus becoming conspicuously radially rimose 3. Pleurocystidia absent ………………………………….. in age; pileipellis elements variable in size and ……………………………….(3) P. seticeps var. seticeps shape with some relatively large (> 60 × > 40 3. Pleurocystidia present.…………………………………. μm)…………………………….…….……(9) P. deceptivus …………………..…...... (4) P. seticeps var. cystidiosus 9. Pileus not rimose or rarely irregularly rimose; pileipellis elements not as variable and large as above…………………………………………………….…….10 Key to Pluteus subsection 10. Pileus greenish drab when young becoming Eucellulodermini species found in the cinnamon drab; stipe pale drab; known only from U.S.A. southern California.………….. ….(6) P. californicus 10. Not as above……………………………………..…….11 1. Pileus whitish, greenish, yellowish, or scarlet 11. Basidiospores predominantly subglobose to colored at maturity…………………………….…….…….2 ovate to broadly ellipsoid……………………..……....12 1. Pileus some shade of brown at maturity...……..6 11. Basidiospores predominantly globose to 2. Pileus scarlet colored; significant percentage of subglobose……………………………………………..……14 basidiospores oblong.…..…(5) P. aurantiorugosus 12. Pleurocystidia frequently lageniform with 2. Not with above combination of characters...….3 long, narrow necks …………….16) P. phlebophorus 3. Pileus colored greenish to yellowish, at least 12. Pleurocystidia frequently broadly lageniform when young…………………………………………..………4 to utriform with short necks to cylindrical/clavate 3. Pileus whitish colored..………………….…..……....5 …………………………………………………………….…....13 4. Pileus colored yellowish to orangish yellow to 13. Pileus dark tan to pale fuliginous, yellowish green to greenish to tawny, hygrophanous; stipe pallid to brownish…………….. hygrophanous; large percentage of pleurocystidia ………………………………………...(13) P. ludovicianus with long, narrow necks…………………………………… 13. Pileus brownish, hygrophanous or not; stipe ……….…(7) P. chrysophlebius var. chrysophlebius with at least some hint of yellow……………………….. 4. Pileus greenish drab when young becoming ……………………………………………(10) P. fulvibadius cinnamon drab, hygrophanous; necks of 14. Basidiospores predominantly globose.…………. pleurocystidia if present typically short and …………….(18) P. pulverulentus var. pseudonanus broad; known only from southern 14. Basidiospores globose to subglobose….……..15 California……………….…………….(6) P. californicus 15. Temperate species; cystidia rare………………….. 5. Pleurocystidia often lageniform with long, ……………………………………….…(17) P. praerugosus narrow necks ………….……….……….(14) P. pallidus 15. Tropical to subtropical species; cystidia 5. Pleurocystidia usually broadly lageniform to usually frequent...……….……....(12) P. jamaicensis utriform and lacking long, narrow necks to cylindrical-clavate……...…...(19) P. roseocandidus Descriptions and illustrations 6. Lamellar edges darkly pigmented…………………. ……………………………………………..…(11) P. homolae Subsection Mixtini 6. Lamellar edges concolorous……….….…..………..7 7. Stipe developing bluish to grayish blue hues at (1) Pluteus eugraptus (Berk. & Broome) the base…………………………………………….………….8 Sacc., Sylloge Fungorum 5: 678. 1887. Fig. 1. 7. Stipe not developing bluish to grayish blue ≡ Agaricus eugraptus Berk. & Broome, J. hues at the base……………………………………….…….9 Linn. Soc., Bot. 11: 535. 1871 (basionym). Type 8 Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 citation: “no. 1148, cum icone.” Basidiospores 5.7–8.8 × 5.3–6.6 µm, Q = 1.07– 1.67 (Lm = 7.2 µm, Wm = 5.8 µm, Qm = 1.24), Types and typifications: brownish pink in mass, subglobose, broadly ellipsoid, ellipsoid to ovate in face and profile Type: CEYLON, CENTRAL PROV.: Kandy Distr., views, circular in end views, apiculate, smooth, on dead wood, VI.1869, coll. GHK Thwaites, walls slightly thickened, subhyaline to pale yellow Thwaites 1148 cum Icon. (holotype of Agaricus in KOH, contents of scattered drops giving grainy eugraptus, K). appearances or not visible. Basidia 20–28 × 7– 10 µm, clavate, tetrasterigmate, thin-walled, Diagnostic characters: Lamellar edges often with granular contents. Pleurocystidia 44– uniformly darkly colored with numerous 72 × 17–22 µm, frequent, lageniform, pedicellate, cheilocystidia containing brown intracellular necks with obtuse apices, readily collapsing, walls pigment; pileipellis elements sphaeropedunculate thin and hyaline in KOH, sometimes with an to clavate to lageniform. apical cap of melleus, amorphous material, often filled with brown intracellular pigment. Selected descriptions and illustrations: Cheilocystidia 33–66 × 8–22 µm, abundant, Singer, Trans. Brit. Mycol. Soc. 39: 198-199, Icon. lageniform to utriform with broad necks and 197, Fig. 48. 1956; Singer, Lloydia 21: 259-260, obtuse apices to clavate to sphaeropedunculate, Icon. 229, Pl. 10, Fig. 20. 1958.; Homola, A readily collapsing, walls thin and hyaline in KOH, Systematic Study of the Section Celluloderma nearly always filled with brown intracellular Fayod of the Genus Pluteus Fries in North pigment. Lamellar trama convergent, hyaline. America, 45-50, Icon. 46-47, Pl. I, Figs. 1-5. 1969; Subhymenium cellular, hyaline. Pileipellis a Homola, Mycologia 64: 1214-1215. 1972; Pegler, A cystoderm, cells 25–89 × 9–40 µm, Preliminary Agaric Flora of East Africa, 276, sphaeropedunculate to clavate to fusiform- Icon. 278, Fig. 58, 1 A-F. 1977; Pegler, Agaric clavate to lageniform with necks narrow to broad Flora of Sri Lanka, 243, Icon. 247, Fig. 52. A-E. at apices, pedicellate, walls thin and hyaline in 1986. KOH, containing brown intracellular pigment. Pileus trama hyaline, septate. Stipitipellis General description: Pileus 1-3 cm in hyphae 4–25 µm wide, septate, walls hyaline and diameter, convex becoming plane to concave, thin, no apparent contents. Caulocystidia not umbonate; surface glabrous to velutinous, dry, common, cylindrical with obtuse apices, 6–12 µm disc often rugulose, cinnamon brown or reddish wide, thin-walled, occasionally with light brown brown (7-A-11, M & P); margin entire, radially intracellular pigment. Clamp connections none. striate from near disc to edge, decurved at Oleiferous hyphae present. Mi. maturity. Stipe 0.7–2.5 cm × 1–2 mm, more or less equal, terete, solid becoming hollow, surface Habit and habitat: Based on the above selected whitish with brown base, occasionally with descriptions and illustrations, frequently solitary scattered fibrils that become more abundant on rotten dicotyledonous wood or soil in tropical, towards the base, fibrils concolorous with the subtropical, and north temperate forests. pileus surface. Lamellae free, close, broad, ventricose, white becoming brownish pink in age, Material examined: U.S.A. Michigan: Emmet edges dark brown. Lamellulae in two tiers. Co., Cross Village, solitary on hardwood, Context of pileus thin, white. Odor and taste not 18.VII.1961, coll. AH Smith, AHS 63525 (MICH). distinctive. Known distribution: Pluteus eugraptus is known from Sri Lanka (Berkeley and Broome Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 9

1871), Argentina (Singer 1956), Bolivia (Singer atromarginatus (Konrad) Kühner, Pluteus 1958), Michigan, U.S.A. (Homola 1972), and atropungens A.H. Sm. & Bartelli, Pluteus Tanzania (Pegler 1977). Despite its apparently umbrosus (Pers. : Fr.) P. Kumm., Pluteus wide distribution, Pluteus eugraptus has been stigmatophorus (Berk. & Broome) Sacc., Pluteus reported only a handful of times. The Smith luctuosus Boud., Pluteus pseudeugraptus E. collection from Michigan is the only known Horak, and Pluteus riograndensis Singer share specimen from the U.S.A. the combination of a pileipellis with cystidioid elements and uniformly darkly pigmented Notes: Since no fresh material or detailed notes lamellar edges. Pluteus eugraptus is certainly a were available for the specimen examined, the distinctive taxon, but more collections of this macromorphological description is a composite extremely rare fungus are needed to understand of those of Singer (1958) and Pegler (1977, 1986). its biology.

The type specimen was not examined. According The Smith collection examined above appears to to Pegler (1986), the type from Sri Lanka be Pluteus eugraptus. However, it would not be (Ceylon) consists of specimens and a colored surprising if this organism turned out to be a sketch at the Royal Botanic Gardens in Kew (K). cryptic species separate from the true P. Both Singer (1956) and Pegler (1986) have eugraptus found in Asia and other isolates from provided complete modern descriptions of the Africa and South America. type specimen. The collection data given for the holotype was adapted from Pegler (1986). (2) Pluteus seticeps (G.F. Atk.) Singer var. seticeps, Lloydia 21: 272. 1958. Figs. 2-6. Based on morphological characters, Pluteus ≡ Leptonia seticeps G.F. Atk., J. Mycol. 8: eugraptus seems to be related to the Pluteus 116. 1902 (basionym). Type citation: seticeps (G.F. Atk.) Singer complex (Homola “McGowan’s woods, July 2, 1902, Ithaca, N. Y., C. 1969). It shares a pileipellis having cystidioid U. herb., No. 9664, and other places.” elements and sometimes pigmented ≡ Leptoniella seticeps (G.F. Atk.) Murrill, cheilocystidia and caulocystidia with members of North American Flora 10: 92. 1917. that complex. Horak (1964) circumscribed ≡ Pluteus psichriophorus var. seticeps Pluteus psychriophorus var. chusqueae E. Horak (G.F. Atk.) Singer, Trans. Brit. Mycol. Soc. 39: as a member of the Pluteus seticeps complex. 214. 1956. ad int. (as Pluteus psychriophorus var. This Argentinean taxon is also characterized by seticeps). This is a nom. inval. darkly colored lamellar edges and a pileipellis = Pluteus nanellus Murrill, North with cystidioid elements, but it grows on American Flora 10: 130. 1917. Type citation: graminoid substrates and has differently shaped “Type collected on a dead log in woods at Lake cystidia. Singer (1969) designated this taxon as Placid, Adirondack Mountains, New York, July Pluteus eugraptus var. chusqueae (E. Horak) 17–29, 1912, W. A. & Edna L. Murrill 73 (herb. N. Singer primarily on the basis of its pigmented Y. Bot. Gard.).” cheilocystidia and cuticle type. We are of the opinion that this taxon probably deserves to be Diagnostic characters: Macroscopically, size elevated to the species rank because of the diminutive; pileus dark brown; stipe white and differences in substrates and cystidia mentioned covered with dark brown fibrils at the base. above. However, we are not familiar enough with Microscopically, pleurocystidia lacking; pileipellis either taxon to formally make such a change. elements sphaeropedunculate to setoid among Regardless, none of the other Pluteus taxa with other shape variations; caulocystidia brown darkly colored gill edges such as Pluteus pigmented. 10 Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107

Selected descriptions and illustrations: hyaline in KOH, lacking visible intracellular Homola, A Systematic Study of the Section contents. Hymenium weakly reviving. Lamellar Celluloderma Fayod of the Genus Pluteus Fries in trama convergent (Atkinson 1902), hyaline. North America, 50-58, Icon. 51-52, Pl. II, Figs. 1- Pileipellis a cystoderm, cells 33–121 × 14–33 μm, 5. 1969; Homola, Mycologia 64: 1215-1218, Icon. sphaeropedunculate to pyriform to setoid with 1212 and 1216, Figs. 1,3 and 9. 1972 (as Pluteus sharp, tapered apices and all pedicellate, walls seticeps). thin and hyaline in KOH, nearly always filled with brown intracellular pigment, cells weakly Singer, Trans. Brit. Mycol. Soc. 39: 214, Icon. 215, adhering to each other in crush mounts. Pileus Fig. 61. 1956 (as Pluteus psychriophorus var. trama hyaline, septate. Clamp connections seticeps). absent.

Smith and Stuntz, Lloydia 21: 130-131. 1958; Leptonia seticeps (original material) Banerjee and Sundberg, Mycotaxon 49: 427, Icon. 428-429, Fig. 26. 1993a (as Pluteus Pileus 5–7 mm in diameter dried, plane; surface nanellus). somewhat velvety; dark brown (6F6–4, M); margin slightly incurved to decurved. Stipe 20– Description of the type specimens: 25 × less than 1 mm, equal to tapered above; Leptonia seticeps (holotype) surface innately striate, basal portion covered with a few dark brown fibrils; ground color Basidiocarps 1–2 cm high. Pileus 1–3 cm in appearing tan in dried state. Lamellae free, diameter, convex becoming expanded; surface broad, ventricose, close, brownish; edges even, smooth, minutely granulose under hand lens; concolorous. walnut brown, disc darker; margin incurved at first, faintly and finely striate. Stipe 2–3 mm Basidiospores 4.4–5.7 × 4.4–5.7 μm, Q = 1.00– thick, even or slightly enlarged below, straight or 1.18 (Lm = 5.3 μm, Wm = 5.0 μm, Qm = 1.05), flesh curved, fibrous striate; surface smooth; whitish colored in mass, globose to subglobose to few below, above concolorous with pileus except ovate in face and profile views, circular in end paler; fleshy; solid. Lamellae slightly adnexed, views, apiculate, smooth, walls slightly thickened, roughly 4 mm broad, elliptical, pale flesh color; subhyaline to pale yellow in KOH, contents edges eroded. Context whitish, very thin. Taste amorphous or with one to many scattered not distinctive. guttules giving grainy appearances. Basidia 12– 22 × 7–9 μm, clavate, tetrasterigmate, walls thin Basidiospores 4.8–6.6 × 4.0–5.7 μm, Q = 1.00– and hyaline in KOH, without visible contents. 1.30 (Lm = 5.7 μm, Wm = 5.1 μm, Qm = 1.12), flesh Pleurocystidia absent. Cheilocystidia 29–47 × colored in mass, globose, subglobose, broadly 11–20 μm, rare, sphaeropedunculate to pyriform, ellipsoid to ovate in face and profile views, walls thin and hyaline in KOH, lacking circular in end views, apiculate, smooth, walls discernable intracellular contents. Lamellar slightly thickened, subhyaline to pale yellow in trama hyaline. Pileipellis a cystoderm, cells 33– KOH, contents of one to many scattered guttules 107 × 17–29 μm, sphaeropedunculate to pyriform giving grainy appearances or not visible. Basidia to lageniform to setoid with sharp, tapered apices 11–19 × 6–7 μm, clavate, tetrasterigmate, walls and all pedicellate, walls thin and hyaline in thin and hyaline in KOH, without visible KOH, nearly always filled with brown contents. Pleurocystidia apparently absent. intracellular pigment, cells weakly adhering to Cheilocystidia 28–44 × 9–22 μm, rare, each other in crush mounts. Pileus trama sphaeropedunculate to pyriform, walls thin and hyaline, septate. Stipitipellis a cutis of cylindrical Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 11 hyphae, 3–11 μm wide, walls thin and hyaline in appearing somewhat areolate, disc smooth to KOH, septate, without apparent contents. rugose; dark brown with darker disc (7F5, M) and Caulocystidia moderately abundant, in fascicles, towards margin lighter (6E5–E6, M); margin terminal elements cylindrical to clavate, 6–9 μm even to finely striate, slightly incurved to broad, walls thin and hyaline in KOH, filled with decurved. Stipe 11–30 × 0.5–1 mm, equal to brown intracellular pigment. Clamp connections tapered above; surface innately striate, basal absent. portion (approximately lower third to half) covered with a few dark brown fibrils concolorous Pluteus nanellus (holotype) with pileus; ground color white; basal tomentum white. Lamellae free, broad, ventricose, close, Pileus 13 mm in diameter, convex, not fully pinkish brown; edges even, concolorous. Context expanded, slightly umbonate; surface, dry, in pileus white. Stipe context white. Odor not glabrous, smooth; pale bay, castaneous dried; distinctive. Spore print pinkish brown. margin rivulose, concolorous. Stipe 2 cm x 1–1.5 mm, equal; surface smooth, glabrous; snow- Basidiospores 4.4–6.6 × 3.5–5.7 μm, Q = 0.92– white. Lamellae free, crowded, ventricose, white 1.36 (Lm = 5.0 μm, Wm = 4.7 μm, Qm = 1.08), becoming salmon colored; edges serrulate. globose, subglobose, broadly ellipsoid, ellipsoid to ovate in face and profile views, circular in end Basidiospores 4.8–6.6 × 4.4–6.6 μm, Q = 1.00– views, apiculate, smooth, walls slightly thickened, 1.27 (Lm = 5.5 μm, Wm = 4.9 μm, Qm = 1.12), subhyaline to pale yellow in KOH, contents globose, subglobose, broadly ellipsoid to ovate in amorphous with one to many scattered guttules face and profile views, circular in end views, providing grainy appearances. Basidia 17–28 × apiculate, smooth, walls slightly thickened, 6–9 μm, clavate, tetrasterigmate, walls thin and subhyaline to pale yellow in KOH, contents of one hyaline in KOH, contents granular or not visible. to many scattered guttules giving grainy Pleurocystidia none. Cheilocystidia 18–50 × 11– appearances or not visible. Basidia 12–23 × 7–9 35 μm, fasciculate, rare, subglobose to μm, clavate, tetrasterigmate, walls thin and sphaeropedunculate to pyriform to clavate- hyaline in KOH, without visible contents. cylindrical, walls thin and hyaline in KOH, Pleurocystidia absent. Cheilocystidia not lacking discernable intracellular contents. observed because lamellar edges are lacking in Lamellar trama convergent, hyaline. the remains of type specimen. Hymenium weakly Subhymenium cellular, hyaline. Pileipellis a revived. Lamellar trama hyaline. Pileipellis a cystoderm, cells 29–132 × 12–37 μm, cystoderm, cells 30–127 × 11–31 μm, sphaeropedunculate to pyriform to lageniform to sphaeropedunculate to pyriform to setoid with setoid with sharp, tapered apices, all pedicellate, sharp, tapered apices and all pedicellate, walls walls thin and hyaline in KOH, nearly always thin and hyaline in KOH, filled with brown filled with brown intracellular pigment, cells intracellular pigment, elements weakly adhering weakly adhering to each other in crush mounts. to each other in crush mounts. Pileus trama Pileus trama hyaline, septate. Stipitipellis a cutis hyaline, septate. Clamp connections absent. of cylindrical hyphae, 3–22 μm wide, walls thin and hyaline in KOH, septate, without apparent All that remains of the holotype is a tiny fragment contents. Caulocystidia moderately abundant, in of the pileus with some broken lamellae. fascicles, terminal elements cylindrical to clavate with hyphae being 4–13 μm wide, walls thin and General description: Pileus 9–20 mm in hyaline in KOH, filled with brown intracellular diameter, convex becoming plane, slight umbo pigment. Clamp connections absent. Oleiferous present or absent; surface granulose, sometimes hyphae present. Mi. 12 Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107

Habit and habitat: Solitary to scattered on State Park, down log in mixed floodplain forest decaying deciduous wood. (beech, hemlock, hickory, maple, oak), 16.VIII.2007, coll. R Healy, NAMA 2007-007 (F, Material examined: U.S.A., ILLINOIS: Cook specimen since destroyed, voucher photograph Co., Sweet Woods Forest Preserve, 29.VI.1956, remains). WISCONSIN: Dane Co., Indian Lake coll. RL Shaffer, RL Shaffer 798 (MICH); Tinley Co. Park, solitary on wood, 24.IX.2004, coll. AS Creek Forest Preserve, scattered on white oak log Methven, Minnis 4-09-20-1 (SIU). in oak woods, 05.VIII.1958. coll. RB Howard and RL Shaffer, RL Shaffer 2059 (MICH). Jackson Known distribution: This species occurs in Co., on campus of Southern Illinois University, eastern parts of the U.S.A. from at least New York gregarious on dead Quercus log, 11.VI.1976, coll. to Missouri and as far south as Tennessee. HD Thiers, HD Thiers 36151 (SFSU); Shawnee National Forest, near Murphysboro, solitary on Notes: The macromorphological descriptions of hardwood log in lowland area, 01.IX.1984, coll. the holotype of Leptonia seticeps and the Southern Illinois Native Plant Society Member, holotype of Pluteus nanellus were adapted from WJ Sundberg 84-9-1-8 (SIU). MICHIGAN: the protologues by Atkinson (1902) and Murrill Chippewa Co., Whitehouse Landing Rd., (1917), respectively. In the protologue, Atkinson probably on Fagus or Acer log, 16.VIII.1965. coll. (1902) cited a specific collection and vaguely RL Homola, RL Homola 1576 (MICH). alluded to others in the original circumscription. Rushmore Woods, on stump in woods, VII.1930, He did not designate any of them as a type as it coll. BO Longyear, BO Longyear, s.n. (MSC as was not required by the International Rules of Pluteus nanus?). MINNESOTA: Clearwater Co., Botanical Nomenclature at that time. However, Bear Paw Point, Itasca State Park, 28.VII.1982, the specifically cited specimen was accepted as coll. R Sorensen, R Sorensen 18 (MIN as Pluteus the holotype since it was implied by Atkinson that thomsonii). MISSOURI: Wayne Co., near Puxico, this was the single most important specimen that Mingo National Wildlife Refuge, scattered on he examined, and it was the only one directly decorticated hardwood log, 20.IX.2003, coll. AS cited. A collection that is part of the original Methven, Minnis 3-09-20-6 (SIU); 16.IX.2006, material could be designated as an epitype for coll. WJ Sundberg, Minnis 6-09-16-3 (SIU); coll. Leptonia seticeps due to the lack of stipe material AM Minnis, Minnis 6-09-16-4 (SIU). NEW in the holotype, but we prefer not to do this here YORK: Tompkins Co., McGowan’s Woods, on since it is more valuable to epitypify with a newer ground, 02.VII.1902, coll. CH Winkler, 9664 collection that may be cultured and also have a (holotype of Leptonia seticeps, CUP); on rotten greater probability of providing DNA sequence log, 11.VII.1902, coll. LAH Whetzel, 9724 data. (original material of Leptonia seticeps, CUP); on very rotten log, 29.VII.1904, coll. HS Jackson, No published accounts of the type collection of 18417 (CUP); Lake Placid, Adirondacks, Leptonia seticeps are present in the literature lignicolous in coniferous or mixed forests at 2000 other than the original description by Atkinson ft (610 m) elevation, 17-29.VII.1912, coll. WA (1902). Singer (1956) examined two authentic Murrill and EL Murrill, WA Murrill and EL collections and reported the presence of Murrill 73 (holotype of Pluteus nanellus, NY). pleurocystidia in one collection. Atkinson (1902) TENNESSEE: Blount Co., Great Smoky stated that there were none or that they were very Mountains National Park, Crib Gap, on rare. Singer (1956) placed P. nanellus in hardwood logs, 26.VII.1988, coll. DE Desjardin, synonymy with Leptonia seticeps, but he did not DED 4634 (SFSU). WEST VIRGINIA: Summers publish any descriptive data. Smith and Stuntz Co., near Athens, River Trail, Pipestem Resort (1958) examined the type of P. nanellus and Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 13 found caulocystidia similar to the elements of the (3) Pluteus seticeps var. cystidiosus Minnis pileipellis (also found in P. seticeps) and no & Sundb., var. nov. Fig. 7. pleurocystidia and did not accept the synonymy MycoBank: 512586 (1958). Homola (1969, 1972), who also did not explicitly publish data on the type of P. nanellus, Etymology: Named for the presence of synonymized the species with P. seticeps pleurocystidia. primarily on the basis of similar cuticular characters. Banerjee and Sundberg (1993a) Latin diagnosis: Varietas Pluteus seticeps var. believed the two species to be distinct based on seticeps similis, sed pleurocystidia adsunt. A the presence of pleurocystidia in P. seticeps and speciebus ceteris pleurocystidiorum forma the absence of them in P. nanellus. differt.

The first author was unable to find pleurocystidia Holotype: U.S.A., MICHIGAN: Chippewa Co., in the holotype of P. seticeps or in other authentic White House Landing, on deciduous wood, collections including the specimen cited in the 05.VII.1965, coll. RL Homola, RL Homola 1340 Singer (1956) study. Although no stipe material (MICH). was present in the holotype collection of Pluteus nanellus (stipe material also lacking in the Diagnostic characters: Macroscopically size holotype of Leptonia seticeps), examination small; pileus dark brown; stipe whitish with dark revealed a lack of pleurocystidia and other brown fibrils on the basal portion. characters identical with P. seticeps. Because of Microscopically, pleurocystidia present; these observations and the examination of pileipellis elements sphaeropedunculate to setoid numerous other collections of this taxon which among other shape variations; caulocystidia also lack pleurocystidia, we believe the two brown pigmented. species are synonyms. Selected descriptions and illustrations: Pluteus seticeps is part of a species complex Homola, A Systematic Study of the Section lacking characters that allow easy differentiation. Celluloderma Fayod of the Genus Pluteus Fries in The European Pluteus podospileus Sacc. & Cub. North America, Icon. 51-52, Pl. II, Figs. 1-5. 1969. discussed below and its numerous taxonomic and nomenclatural variations all differ by the Description of the type specimens: Pileus presence of pleurocystidia. Other species with 10–25 mm diameter dried, convex becoming related types of pileipelli including the Asian plane, umbo present or absent; surface Pluteus delicatulus C.K. Pradeep & K.B. Vrinda, granulose, disc smooth to rugose; dark brown Pluteus eugraptus (Berk. & Broome) Sacc., (Vandyke brown 6F6, M) dried; margin even to Pluteus minutus Pat., Pluteus psichriophorus finely striate, slightly incurved to decurved. Stipe (Berk. & Broome) Sacc., Pluteus stigmatophorus 15–30 × 0.5–3 mm dried, equal to tapered above; (Berk. & Broome) Sacc., the South American surface with dark brown fibrils at base; whitish or Pluteus agriensis Singer, Pluteus pallid when dried. Lamellae free, broad, pseudeugraptus E. Horak, Pluteus subminutus ventricose, close, pinkish brown; edges even, Singer, Pluteus substigmaticus Singer, Pluteus concolorous. Pileus context whitish. Spore print umbrinoalbidus Singer, and Pluteus varzeicola pinkish brown. Singer, and the tropical American Pluteus burserae Singer, Pluteus dennisii Singer, and Basidiospores 4.4–7.5 × 4.4–6.2 μm, Q = 1.00– Pluteus venosus Singer all differ from P. seticeps 1.42 (Lm = 5.7 μm, Wm = 4.9 μm, Qm = 1.16), few in the possession of pleurocystidia. globose to mostly subglobose, broadly ellipsoid, 14 Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 ellipsoid to ovate in face and profile views, Known distribution: Pluteus seticeps var. circular in end views, apiculate, smooth, walls cystidiosus as described above is only known slightly thickened, subhyaline to pale yellow in from Michigan, U.S.A. KOH, contents not visible or of one to many scattered guttules creating grainy appearances. Notes: The type description is a composite of Basidia 17–31 × 6–9 μm, clavate, tetrasterigmate, data from of all of the examined collections. walls thin and hyaline in KOH, contents granular or not apparent. Pleurocystidia 36–58 × 14–30 Some specimens from Michigan matching the μm, scattered, few to common, broadly macroscopic description of P. seticeps were found lageniform with pedicels and short necks having to possess pleurocystidia. These seem to fit well broad, obtuse apices to ellipsoid to clavate- with the interpretation of Pluteus podospileus f. cylindrical, walls thin and hyaline in KOH, no minutissimus (Maire) Vellinga (Vellinga 1990, apparent contents, apices at times covered with Breitenbach and Kränzlin 1995), a European amorphous, mucilaginous material. taxon discussed below. Homola (1972) sent Cheilocystidia 37–64 × 12–26 μm, fasciculate, similar material to Orton who felt that it was rare, sphaeropedunculate to pyriform to clavate- synonymous with this European taxon. Homola cylindrical, walls thin and hyaline in KOH, (1969, 1972) made no mention of any material lacking discernable intracellular contents. lacking pleurocystidia. The reason for this is Lamellar trama convergent, hyaline. befuddleing as we found none in several Subhymenium cellular, hyaline. Pileipellis a collections cited in the Homola works. Based on cystoderm, cells 34–108 × 10–25 μm, the absence of pleurocystidia in most specimens, sphaeropedunculate to pyriform to broadly it is our opinion that North American populations lageniform to setoid with sharp, tapered apices of P. seticeps are genetically distinct from related and all pedicellate, walls thin and hyaline in taxa in Europe and have, for the most part, lost KOH, nearly always filled with brown their pleurocystidia. We prefer to assign this new intracellular pigment, cells weakly adhering to varietal name, Pluteus seticeps var. cystidiosus, each other in crush mounts. Pileus trama to those North American populations with some hyaline, septate. Stipitipellis a cutis of cylindrical pleurocystidia in part to promote additional hyphae, 3–26 μm wide, walls thin and hyaline in studies. Future work on new collections in the KOH, septate, without apparent contents. U.S.A. should determine the relative abundance Caulocystidia moderately abundant, in fascicles, of populations with and without pleurocystidia terminal elements cylindrical to clavate, 5–22 μm and whether or not there is gene flow between wide, walls thin and hyaline in KOH, filled with the two varieties. Additional studies, biological brown intracellular pigment. Clamp connections or molecular or both, could also be performed in absent. Oleiferous hyphae present. Mi. order to determine if European, North American, and other taxa (see discussion of Pluteus seticeps Habit and habitat: Scattered on deciduous var. seticeps) are conspecific and the possibility wood. of introductions of European and other foreign species to the U.S.A. may be considered. Material examined: U.S.A., MICHIGAN: Chippewa Co., White House Landing, on (4) Pluteus thomsonii (Berk. & Broome) deciduous wood, 05.VII.1965, coll. RL Homola, Dennis, Trans. Brit. Mycol. Soc. 31: 206. 1948. RL Homola 1340 (holotype of Pluteus seticeps (as Pluteus thomsoni). Fig. 8. var. cystidiosus, MICH). Tahquamenon Falls ≡ Agaricus thomsonii Berk. & Broome, State Park, on hardwood, 02.VII.1952, coll. AH Ann. Mag. Nat. Hist. 17: 131. 1876 (basionym). (as Smith, AH Smith 39109 (MICH). Agaricus thomsoni). Type citation: “Amongst Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 15 grass in a plantation. West Farleigh. Found in 90-91, 94-95, and 96-97 Figs. 22-25, 41-44, and company with Dr. Thomson.” 62. 1986; Vellinga, Pluteus, In: Bas et al., Flora ≡ Entoloma thomsonii (Berk. & Broome) Agaracina Neerlandica, Vol. 2, 46-47, Icon. 47, Sacc., Sylloge Fungorum 5: 693. 1887. (as Fig. 26. 1990; Breitenbach and Kränzlin, Fungi of Entoloma thompsoni). Switzerland, Vol. 4, 132, Icon. 132-133, = Pluteus cinereus Quél., Ann. Sci. Nat. photograph and Figs. A-E. 1995. Bord. (Suppl.) 14: 3. 1884. = Pluteus reisneri Velen., Ceské Houby Description of the type specimens: 610. 1921. Agaricus thomsonii (lectotype) = Pluteus pilatii Velen., Mykologia 6: 25. 1929. (as Pluteus pilati). Pileus 1.25 (3.2 cm) to nearly 2 inches (5 cm) in = Pluteus cinereus var. venosus Vacek, diameter, plane; surface adorned with raised Studia Bot. Cechosl. 11: 47. 1948. radiating ribs, tomentose; gray. Stipe 1.5 inches = Pluteus cinereus Quél. f. evenosus (reported as lines, but must have been an error) Kühner, Bull. Soc. Mycol. France 72: 181. 1956. (3.8 cm) x 2 lines (0.4 cm); surface fibrillose, ≡ Pluteus thomsonii (Berk. & Broome) tomentose. Lamellae broad. Dennis f. evenosus (Kühner) Wuilb., Miscellanea Mycologica 15: 16. 1986. The lectotype was not examined for ≡ Pluteus thomsonii (Berk. & Broome) micromorphological characters. See Dennis Dennis f. evenosus (Kühner) Citérin & Eyssart., (1958) for a description of such characters. Doc. Mycol. 28: 57. 1998. Isonym. General description: Pileus 1.2–2.5 cm in Types and typifications: diameter, convex to plano-convex, slight umbo present or not; surface dry, glabrous, rugose to Type (Agaricus thomsonii): ENGLAND: West appearing reticulate ridged, micaceous under Kent, West Farleigh (near Maidstone), coll. MJ hand lens, hygrophanous; dark gray-brown to Berkeley, MJ Berkeley, s.n. (K(M) 93764) (K as rich dull dark brown (6F6, M), disc and ridges Pluteus thomsonii)―Lectotype designated concolorous, paler brown elsewhere (5E4, M); here. margin decurved, striate, even. Stipe 2.1–5 cm x 2-3 mm at apex, equal to tapered above; surface Diagnostic characters: Macroscopically, innately fibrillose with few scattered brown pileus grayish to brown; usually with a highly fibrils, twisted; grayish white; stuffed becoming wrinkled to reticulate surface; stipe whitish. hollow; basal tomentum white. Lamellae free, Microscopically, lamellar cystidia, especially close, thin, white to gray becoming pinkish; edges cheilocystidia, with short to quite long apical smooth, concolorous. Lamelullae in 1–2 tiers. projections; pileipellis elements pyriform to Context in pileus white. Stipe context white. clavate to broadly lageniform to setoid. Odor not distinctive.

Selected descriptions and illustrations: Basidiospores 5.3–9.2 × 4.8–7.0 μm, Q = 1.00– Homola, A Systematic Study of the Section 1.62 (Lm = 7.2 μm, Wm = 6.0 μm, Qm = 1.21), Celluloderma Fayod of the Genus Pluteus Fries in subglobose, broadly ellipsoid, ellipsoid, ovate to North America, 60-65, Icon. 61-62, Pl. IV, Figs. 1- rarely globose to oblong to inequilateral in face 6. 1969; Homola, Mycologia 64: 1219-1220, Icon. and profile views, circular in end views, apiculate, 1212 and 1216, Figs. 6 and 10. 1972; Orton, smooth, walls slightly thickened, subhyaline to British Fungus Flora: Agarics and Boleti, Vol. 4, pale yellow in KOH, contents not visible or of one Pluteaceae: Pluteus and Volvariella, 56-58, Icon. to many scattered guttules giving grainy 16 Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 appearances. Basidia 17–39 × 6–12 μm, clavate, Habit and habitat: Solitary to scattered to tetrasterigmate, walls thin and hyaline in KOH, gregarious on rotting wood of deciduous origin to contents granular or not apparent. terrestrial presumably on buried wood or soil rich Pleurocystidia 39–68 × 10–22 μm with apical in decayed organic matter. projection, projection 1–21 × 1–3 μm, scattered, none to few to common, lageniform with pedicels Material examined: ENGLAND: West Kent, and short necks having broad, obtuse apices to West Farleigh (near Maidstone), coll. MJ clavate to pyriform to utriform and occasionally Berkeley, MJ Berkeley, s.n. (K(M) 93764) with a short apical mucro to long rostrum, walls (designated lectotype of Agaricus thomsonii, K as thin and hyaline in KOH, no apparent contents, Pluteus thomsonii). U.S.A., CALIFORNIA: Marin apices at times covered with amorphous, Co., Audubon Canyon Ranch, Pitcher Canyon, mucilaginous material. Cheilocystidia 30–86 × solitary on decaying wood in mixed evergreen 7–25 μm with apical projection, projection 1–33 forest, 3.II.1980, coll. C Calhoun, C Calhoun 80- × 1–4 μm, crowded, lageniform with pedicels and 1536 (SFSU). Santa Cruz Co., vicinity of Boulder short necks having broad, obtuse apices to clavate Creek, gregarious on fallen branches, etc. in to utriform and often with a short apical mucro to mixed woods, 26.XI.1974, coll. HD Thiers, HD long rostrum, walls thin and hyaline in KOH, Thiers 33092 (SFSU). ILLINOIS: Jackson Co., lacking discernable intracellular contents, not Carbondale, Marberry Arboretum, solitary on uncommonly covered with an apical cap of ground in hardwood forest, 27.VII.1998, coll. AM amorphous, mucilaginous material. Lamellar DeJarnett, AM DeJarnett 120 (SIU); Union Hill trama convergent, hyaline. Subhymenium Subdivision, southeast of Carbondale, solitary cellular, hyaline. Pileipellis a cystoderm, cells among litter under hardwoods, 04.VIII.1979, coll. 25–105 × 10–33 μm with apical projection WJ Sundberg, WJ Sundberg 4385 (SIU). Shelby included in the lengths, pyriform to short- Co., near Shelbyville, Hidden Springs State elliptical to clavate to broadly lageniform to Forest, solitary on wood, 23.IX.2006, coll. AM setoid and often with a short apical mucro to long Minnis, Minnis 6-09-23-1 (SIU). KENTUCKY: rostrum, walls thin and hyaline in KOH, nearly Lyon Co., Ecological Education Area, Land always filled with brown intracellular pigment, Between the Lakes, scattered on well decomposed cells weakly adhering to each other in crush log, 08.VI.1973, coll. WJ Sundberg and J mounts. Pileus trama hyaline, septate. Richardson, WJ Sundberg 2253 (SIU). Stipitipellis a cutis of cylindrical hyphae, 2–24 MICHIGAN: Livingston Co., ES George Reserve, μm wide, walls thin and hyaline in KOH, septate, 29.VI.1970, coll. F Hoseny, F Hoseny, s.n. without apparent contents. Caulocystidia (MICH); George Reserve, on deciduous rotten log moderately abundant, in fascicles, terminal (probably Quercus), 16.VII.1964, coll. RL elements similarly shaped to cells of the Homola, RL Homola 930 (MICH). Washtenaw pileipellis, pyriform to clavate to fusoid- Co., Ann Arbor, around Quercus stumps, ventricose to cylindrical and at times with a short 02.VII.1935, coll. AH Smith, AH Smith 1458 apical mucro to long rostrum, hyphae 8–29 μm (MICH); Leslie, on old stumps in woods, wide, apical projection 12–24 × 2–3 μm, walls 29.VII.1902, coll. BO Longyear, BO Longyear, thin and hyaline in KOH, without visible s.n. (MSC as Pluteus admirabilis). MISSOURI: contents, rarely covered with an apical cap of Wayne Co., near Puxico, Mingo National Wildlife amorphous, mucilaginous material. Clamp Refuge, solitary on wood, 20.IX.2003, coll. J connections none. Oleiferous hyphae present. Justice, Minnis 3-09-20-4 (SIU); 16.IX.2006, Mi. coll. AS Methven, Minnis 6-09-16-1 (SIU); coll. AM Minnis, Minnis 6-09-16-2 (SIU). NORTH CAROLINA: IX.1918, coll. HC Beardslee, Jr., HC Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 17

Beardslee, Jr. 18128 (MICH as Pluteus No other species with a pileipellis having phlebophorus). cystidioid elements has the rostrate cystidia and gray to brown pileus coloration found in Pluteus Known distribution: Pluteus thomsonii is a thomsonii. Pluteus laetus Singer shares a similar widespread fungus reported from Africa (Vellinga type of pileipellis structure and rostrate cystidia, 1990, Breitenbach and Kränzlin 1995), Asia but it differs in the possession of a reddish (Imazeki et al. 1988, Breitenbach and Kränzlin colored pileus (Singer 1958, 1961). Pluteus 1995), Europe (Orton 1986, Vellinga 1990, insidiosus Vellinga & Schreurs (1985) differs in Breitenbach and Kränzlin 1995), North America having a cystoderm pileipellis lacking cystidioid (Homola 1969, 1972), and South America elements. Pluteus diverticulatus Corriol is nearly (Wartchow et al. 2004). It is seemingly rare, but identical and reportedly differs in having some widespread in the U.S.A. apically branched elements in the pileipellis and stipitipellis and similarly branched cheilocystidia (Corriol 2003). Pluteus neotropicalis Rodríquez- Notes: The macromorphological description of Alcántar differs in the length of the projection of the lectotype was translated and modified from the rostrate cheilocystidia among other the protologue (Berkeley and Broome 1876). We characters (Rodríguez et al. 2008). Rodríguez et only examined a photocopy image of one sheet of al. (2008) believe that material they cited as original material found at the Royal Botanic Pluteus thomsonii from Mexico in previous Gardens in Kew (K). However, Dennis (1948) papers and possibly material cited by Wartchow provided a description and illustrations of this et al. (2004) belong to Pluteus neotropicalis. The material. Berkeley and Broome (1876) did not first author has observed several unidentified cite any specific specimens, but rather provided Pluteus collections possessing rostrate cystidia limited collection data. Dennis (1948) mentions from the U.S.A. However, this material clearly two sheets of specimens with identical labels. As belongs to Pluteus section Hispidoderma. A far as we know, no author has officially critical re-evaluation of Pluteus thomsonii is designated a single type specimen, and the vague needed on a worldwide basis to determine if protologue does not constitute typification. The cryptic species are present. Particularly, the existence of two duplicates with neither distinctly variable presence or absence of pleurocystidia as designated as a lectotype as implied by Dennis well as the length of the projection on the rostrate (1948) leads to some confusion. Hence, we have cheilocystidia should be investigated for designated a lectotype from a single specimen of taxonomic value. original material. Subsection Eucellulodermini Numerous synonyms listed above have been discussed at length in the literature by numerous (5) Pluteus aurantiorugosus (Trog) Sacc., authors including Vellinga (1990), Rodríguez and Hedwigia 35: 5. 1896. Figs. 9–11. Guzmán-Dávalos (1999), and Wartchow et al. ≡ Agaricus aurantiorugosus Trog, Mitth. (2004) among others. Based on this literature Naturf. Ges. Bern No. 388: 32. 1857 (basionym). and the protologues for these species, we list Type citation: “An einem Pappelbaum an der them as synonyms as well. Specimens with pilei Zulg. Otth.” having distinctly veined and smooth forms that = Pluteus leoninus var. coccineus Massee, British were described as separate taxa in the literature Fungi Flora 2: 290. 1893. are here listed as synonyms because of the ≡ Pluteus coccineus (Massee) J.E. Lange, variability of this character. Flora Agaricina Danica 2: 88. 1937 (1936). = Pluteus caloceps G.F. Atk., Ann. Mycol. 7: 373. 18 Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107

1909. Type citation: “C. U. herb., No. 19428, on Basidiospores 5.3–8.8 × 3.5–5.7 μm, Q = 1.17– very rotten wood, woods north of Varna, near 1.82 (Lm = 7.2 μm, Wm = 4.7 μm, Qm = 1.53), Ithaca, N. Y., Oct. 1, 05, C. W. Edgerton; No. ovate, broadly ellipsoid, ellipsoid to oblong often 18770, ground, Dead Lake, Michigan, Oct. 15, with constrictions at the midportions in face and 1904, C. H. Kauffman.” profile views, circular in end views, apiculate, smooth, walls slightly thickened, subhyaline to Types and typifications: pale yellow in KOH, contents predominantly not visible or rarely of one to many scattered Type (Pluteus caloceps): U.S.A., MICHIGAN: guttules. Basidia 18–24 × 7–9 μm, clavate, Washtenaw Co., Dead Lake, on ground, tetrasterigmate, walls thin and hyaline in KOH, 15.X.1904, coll. CH Kauffman, CUP-A-018770 contents rarely granular to usually with no (CUP)—Lectotype designated here. apparent contents. Pleurocystidia 37–70 × 13–23 μm, scattered, infrequent in abundance, Diagnostic characters: Pileus bright orange lageniform with pedicels and relatively short to to scarlet; basidiospores ovate, often oblong; long necks having broad to narrow, obtuse apices pileipellis lacking cystidioid elements. to utriform, walls thin and hyaline in KOH, lacking visible intracellular contents, at times Selected descriptions and illustrations: covered with an apical cap of amorphous, Singer, Trans. Brit. Mycol. Soc. 39: 195. 1956.; mucilaginous material. Cheilocystidia 33–46 × Homola, A Systematic Study of the Section 17–28 μm, crowded, pyriform to clavate to Celluloderma Fayod of the Genus Pluteus Fries in lageniform, walls thin and hyaline in KOH, North America, 115-121, Icon. 116-117, Pl. XI, without obvious intracellular contents, some Figs. 1-5. 1969; Homola, Mycologia 64: 1238- covered with an apical cap of amorphous, 1240. 1972; Orton, British Fungus Flora: Agarics mucilaginous material. Lamellar trama and Boleti, Vol. 4, Pluteaceae: Pluteus and convergent, hyaline. Subhymenium cellular, Volvariella, 50-51. 1986; Vellinga, Pluteus, In: hyaline. Pileipellis a cystoderm, cells 28–66 × Bas et al., Flora Agaracina Neerlandica, Vol. 2, 19–34 μm, globose to sphaeropedunculate to 55, Icon. 55, Fig. 37. 1990 (as Pluteus pyriform and pedicellate to apedicellate, walls aurantiorugosus). thin and hyaline in KOH, without visible intracellular pigment in dried material, cells Singer, Trans. Brit. Mycol. Soc. 39: 196. 1956 (as tightly adhering to one another in crush mounts. Pluteus caloceps). Pileus trama hyaline, septate. Stipitipellis a cutis of cylindrical hyphae, 3–23 μm wide, walls thin Description of the type specimens: and hyaline in KOH, septate, without apparent Pluteus caloceps (designated lectotype) contents. Basal tomentum composed of cylindrical hyphae, 3–6 μm wide, walls thin and Basidiocarps 2.5–6 cm high. Pileus 2.5–4.5 cm hyaline in KOH, septate. Clamp connections in diameter, convex, umbonate; surface smooth absent. to slightly granular to rimose towards the margin; orpiment orange to vermillion, disc The pileus of the lectotype specimen is partially vermillion, bright vermillion color remaining covered with growth of a contaminant fungus. apparent in dried specimens. Stipe 3–5 mm thick, fibrous striate, pallid. Lamellae free, General description: Pileus 1.5–5.2 cm in broadly elliptical to subventricose, rounded diameter, conic to convex becoming expanded, behind, pale dull flesh color; edges minutely umbonate, umbo obtuse to acute, wavy and split floccose. Context white. at margin; surface finely appressed-fibrillose and Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 19 glistening in places under hand lens, cuticle not Stipitipellis a cutis of cylindrical hyphae, 2–25 separable, dull; vivid reddish orange to bright μm wide, walls thin and hyaline in KOH, septate, scarlet to bright vermillion, rarely bright orange- without apparent contents. Basal tomentum yellow at margin; margin finely striatulate to 5 composed of cylindrical hyphae, 3–6 μm wide, mm inwards. Stipe 1.5–4.5 cm × 1.5–8 mm, walls thin and hyaline in KOH, septate. Clamp more or less equal with base slightly thickened, connections absent. Oleiferous hyphae present. curved; surface shiny, fibrillose-striate above, Mi. fibrillose and subscaly below; pale orangish to yellowish to whitish above, pale yellow to whitish below, base orange-red to pale greenish yellow- Habit and habitat: Scattered to gregarious to translucent; fragile; basal tomentum white. cespitose on interior of tree stumps or other Lamellae free, up to 3.5 mm broad, unequal, not rotten wood in hardwood forests mostly of Acer, forked; whitish to pale tan, bruising yellow; edges Aesculus, Fagus, Fraxinus, Quercus, Tilia, and slightly fimbriate. Pileus context whitish Ulmus. becoming yellow after exposure, yellowish at cuticle, far less abundant at margin, fragile. Stipe context solid, fibrous, concolorous with exterior. Material examined: U.S.A., CALIFORNIA: Spore print pale pinkish. Santa Cruz Co., San Lorenzo River bank, H Cowell State Park, gregarious in dead wood of Basidiospores 5.3–7.9 × 4.4–6.2 μm, Q = 1.09– live Acer negundo, 15.VIII.1978, coll. R Kerrigan, 1.50 (Lm = 6.7 μm, Wm = 5.2 μm, Qm = 1.29), very R Kerrigan 1052 (SFSU). ILLINOIS: Champaign few subglobose, mostly ovate, broadly ellipsoid to Co., Urbana, Brownfield Woods, in hollow of ellipsoid in face and profile views, circular in end Aesculus glabra, 29.IX.1980, coll. SG Saupe, SG views, apiculate, smooth, walls slightly thickened, Saupe 364 (ILLS); 28.X.1980, coll. SG Saupe, SG subhyaline to pale yellow in KOH, contents of one Saupe 377 (ILLS). MICHIGAN: Marquette Co., to many scattered guttules or not visible. Basidia Elm Creek, Ives Lake, inside an Ulmus stump on 21–36 × 7–11 μm, clavate, tetrasterigmate, walls very soft rotten wood, 28.VII.1971, coll. KA thin and hyaline in KOH, contents granular to Harrison, KA Harrison 10540; 02.VIII.1971, coll. agranular. Pleurocystidia 44–79 × 14–28 μm, KA Harrison, KA Harrison 10610 (MICH as scattered, infrequent to common in abundance, Pluteus caloceps). Oakland Co., Proud Lake, lageniform with pedicels and relatively short Fagus tree, 03.IX.1950, coll. AH Smith, AH necks having broad, obtuse apices to clavate to Smith 36176 (MICH). Washtenaw Co., Dead utriform, walls thin and hyaline in KOH, lacking Lake, on ground, 15.X.1904, coll. CH Kauffman, apparent intracellular contents, rarely covered CUP-A-018770 (designated lectotype of Pluteus with an apical cap of amorphous, mucilaginous caloceps, CUP); Dieterle’s Woods, inside fallen material. Cheilocystidia 29–56 × 10–22 μm, hollow log, 30.X.1970, coll. F Hoseny, F Hoseny crowded, pyriform to clavate, walls thin and 1740 (MICH). MINNESOTA: Rice Co., Near hyaline in KOH, lacking apparent contents. Nerstrand Woods State Park, gregarious to Lamellar trama convergent, hyaline. cespitose in tree stumps, 14.IX.1962, coll. MG Subhymenium cellular, hyaline. Pileipellis a Weaver, MGW 9-14-62-N-2 (MIN 726937) cystoderm, cells 23–39 × 13–29 μm, globose to (MIN); 28.IX.1962, coll. MG Weaver, MGW 9- sphaeropedunculate to pyriform and pedicellate 28-62-N-2 (MIN 726936) (MIN) Nerstrand State to apedicellate, walls thin and hyaline in KOH, Park area, Section 16, Wheeling Township, without visible intracellular pigment in dried scattered to gregarious in tree stumps, material, cells tightly adhering to one another in 29.VI.1963, coll. MG Weaver, MGW 6-29-63-N-1 crush mounts. Pileus trama hyaline, septate. (MIN). 20 Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107

Known distribution: Pluteus Pluteus rubrotomentosus Singer has a similar aurantiorugosus is found with wide distributions pileus coloration, but it possesses a filamentous in Europe and North America (Vellinga 1990). It pileipellis (Singer 1958) rather than the cellular has also been reported from Asia (Imazeki et al. pileipellis of P. aurantiorugosus. Pluteus 1988). ochraceus E. Horak shares approximating features (Horak 1964) with P. rubrotomentosus Notes: The macromorphological description of and differs for the same reason. Pluteus laetus the designated lectotype of Pluteus caloceps was and its two varieties also have similar pileus modified from the protologue (Atkinson 1909). A coloration (Singer 1961). These taxa have a holotype was not formally designated in the Mixtini-type pileipellis and rostrate cheilocystidia original description of P. caloceps and Singer’s (Singer 1961) which differentiates them from P. (1956) use of the term type is not sufficient for aurantiorugosus, a species that has a cellular lectotypification since no specimen data was pileipellis lacking cystidioid elements and no cited. Since there are two syntypes, we rostrate cheilocystidia. Finally, Pluteus laetifrons designated one of the specimens cited in the (Berk. & M.A. Curtis) Sacc. and its valid and protologue as the lectotype. We did not study the provisional varieties discussed by Singer (1958) remaining syntype at Cornell University Plant share a similar pileus coloration to P. Pathology Herbarium (CUP). The type of Pluteus aurantiorugosus. Pluteus laetifrons is aurantiorugosus was not examined. According distinguished by having more or less globose to Singer (1956), this type should be located in basidiospores (Singer 1958). The Singer taxa Paris at the Muséum National d'Histoire should be studied in detail for comparative Naturelle (P). However, we were unable to locate purposes since no one has critically studied them it via correspondence with the museum’s staff. since he published the original descriptions. This specimen needs to be officially designated as a lectotype. Should North American isolates be shown to be distinct from those in Europe at the species rank, The nomenclatural history of P. aurantiorugosus Pluteus caloceps would be the correct name for has been summarized by Homola (1969, 1972). the isolates from North America. We found no In short, Singer (1956) and Orton (1960) morphological basis for such a distinction. determined that P. aurantiorugosus was the correct name and that both P. caloceps and P. (6) Pluteus californicus McClatchie, coccineus were synonyms. Based on these works, Proceedings of the Southern California Academy we have also accepted them as synonyms. Singer of Sciences 1: 384. 1897. Type citation: “In soil (1956) also believed that Pluteus aurantiacus and on decaying leaves and twigs under trees, Murrill was a synonym of P. aurantiorugosus. Pasadena and Compton.” Lectotypification Smith and Stuntz (1958) disagreed with Singer citation [first step], Banerjee and Sundberg, and placed P. aurantiacus near Pluteus Mycotaxon 49: 418. 1993a: “TYPE: McClatchie, s. admirabilis (Peck) Peck. Banerjee and Sundberg n. Holotype, NY!.” (as holotype). Fig. 12. (1993a) did not reach a conclusion on the matter of synonymy between these two taxa. Based on Types and typifications: our examination of type collections, P. aurantiacus is not a synonym of P. Type (Pluteus californicus): U.S.A., aurantiorugosus (see discussion for Pluteus CALIFORNIA: Pasadena, among decaying leaves chrysophlebius (Berk. & Ravenel) Sacc. var. and twigs under trees, 13.I.1895, coll. AJ chrysophlebius). McClatchie, McClatchie 1323 (ID 775457) (NY)— Lectotype designated here [second step]. Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 21

Diagnostic characters: Macroscopically, clavate to pyriform and pedicellate with few pileus hygrophanous; greenish drab becoming having a single short mucro, walls thin and cinnamon-drab; stipe pale drab. Microscopically, hyaline in KOH, containing brown intracellular pleurocystidia few; lageniform with short broad, pigment, cells weakly adhering to one another in necks; pileipellis lacking cystidioid elements. crush mounts. Pileus trama hyaline, septate. Stipitipellis a cutis of cylindrical hyphae, 3–22 Selected descriptions and illustrations: μm wide, walls thin and hyaline in KOH, septate, Smith and Stuntz, Lloydia 21: 119. 1958; Banerjee without apparent contents. Clamp connections and Sundberg, Mycotaxon 49: 418, Icon. 416-417, absent. Fig. 6. 1993a. Habit and habitat: Gregarious on debris under Description of the type specimens: trees.

Pileus 20–40 mm in diameter, convex becoming Material examined: U.S.A., CALIFORNIA: expanded; surface rugose-venose, hygrophanous; Pasadena, among decaying leaves and twigs greenish drab becoming cinnamon-drab; margin under trees, 13.I.1895, coll. AJ McClatchie, occasionally briefly striate. Context 2-3 mm thick McClatchie 1323 (ID 775457) (designated at disc becoming thinner towards margin. lectotype of Pluteus californicus, NY). Lamellae 3–5 mm broad, crowded, thin, elliptical, grayish white becoming grayish flesh Known distribution: Pluteus californicus is colored. Stipe 20–60 mm x 2–3 mm, nearly only known from the original collection from the straight; surface shiny; pale drab; hollow; fibrous. southern portion of California, U.S.A. (McClatchie 1897). Basidiospores 6.6–8.8 × 5.7–7.9 μm, Q = 1.00– 1.46 (Lm = 7.8 μm, Wm = 6.7 μm, Qm = 1.17), few Notes: The macromorphological description of globose, subglobose to ovate to predominantly the type was adapted from the protologue broadly ellipsoid to ellipsoid in face and profile (McClatchie 1897). A holotype does not exist views, circular in end views, apiculate, smooth, since the protologue does not cite a specific walls slightly thickened, subhyaline to pale yellow specimen as a type and only includes limited in KOH, contents not visible or of one to many collection data. Banerjee and Sundberg (1993a) scattered guttules. Basidia 12–29 × 7–13 μm, lectotypified the species in spite of their use of clavate, tetrasterigmate, walls thin and hyaline in the term holotype (ICBN Art. 9.8, McNeill et al. KOH, contents granular to lacking. 2006). However, duplicate or otherwise Pleurocystidia 42–55 × 13–18 μm, not common indistinguishable specimens exist at NY, and in abundance, lageniform having pedicels and Banerjee and Sundberg (1993a) did not provide short necks with broad, obtuse apices, frequently enough information to differentiate the collapsing, walls thin and hyaline in KOH, collections. Thus, we have designated a second without visible intracellular contents, some step lectotype from original material according to covered with an apical cap of amorphous, ICBN Art. 9.15 (McNeill et al. 2006). mucilaginous material. Cheilocystidia 24–55 × 15–26 μm, crowded, lageniform having pedicels Pluteus californicus remains a poorly known and short necks with broad, obtuse apices to species. No one has seen fresh material and clavate to pyriform, walls thin and hyaline in published on it since McClatchie described the KOH, lacking visible contents. Lamellar trama species. The dried specimens lack any truly hyaline. Pileipellis a cystoderm, cells 18–50 × distinctive features, and the basidiocarp 11–20 μm, globose to sphaeropedunculate to colorations described by McClatchie serve as the 22 Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 most important distinguishing features. This much decayed wood in mixed woods at Unaka opinion on coloration was shared by Smith and Springs, Tennessee, August 18–24, 1904, W. A. Stuntz (1958). Smith and Stuntz (1958) reported Murrill 840 (herb. N. Y. Bot. Gard.).” yellowish hues in the stipe, but this was not = Pluteus rugosidiscus Murrill, North American mentioned by McClatchie, and their depiction Flora 10: 129. 1917 (basionym). Type citation: probably resulted from an erroneous “Type collected on dead wood in deciduous interpretation made by Murrill (1917). woods at Falls Church, Virginia, July 2–6, 1904, W. A. Murrill 111 (herb. N. Y. Bot. Gard.).” Pluteus californicus is similar to Pluteus chrysophlebius (Berk. & Ravenel) Sacc. in that Types and typifications: they share greenish hues in hygrophanous pilei. The latter differs in having a yellowish stipe, Type (Agaricus admirabilis): Icon. Type more abundant pleurocystidia, and lageniform illustration by C.H. Peck of Agaricus admirabilis pleurocystidia usually having longer and Peck: “123, Ag. (Pluteus) admirabilis n. sp., on narrower necks. Pluteus fulvibadius Murrill is old logs in woods, Gregg, Sept.” (NYS set apart from P. californicus by its yellowish illustration-I-3001) (NYS)—Lectotype stipe. designated here.

More collections from the environs of the type are Diagnostic characters: Macroscopically, needed. Until this species is found again, its pileus yellowish to yellowish green to orangish application will remain difficult. yellow to occasionally tawny; hygrophanous; stipe yellow. Microscopically, pleurocystidia (7) Pluteus chrysophlebius (Berk. & lageniform not of the broad type as in Pluteus Ravenel) Sacc., Sylloge Fungorum 5: 678. 1887., fulvibadius and Pluteus romellii; basidiospores var. chrysophlebius Figs. 13–20. primarily ovate to broadly ellipsoid; pileipellis ≡ Agaricus chrysophlebius Berk. & lacking cystidioid elements. Ravenel, in Berk. & M. A. Curtis, Ann. Mag. Nat. Hist. III. 4: 289. 1859 (basionym). Type citation: Selected descriptions and illustrations: “On putrid hickory logs, September, South Homola, A Systematic Study of the Section Carolina, H. W. Ravenel.” Lectotypification Celluloderma Fayod of the Genus Pluteus Fries in citation, Singer, Trans. Brit. Mycol. Soc. 39: 196. North America, 106-112, Icon. 107-108, Pl. X, 1956: “The type from South Carolina on rotten Figs. 1-5. 1969; Homola, Mycologia 64: 1235- Carya stumps, coll. Ravenel, det. Berkeley (FH)”. 1236, Icon. 1233, Fig. 14. 1972 (as Pluteus = Agaricus admirabilis Peck, Rep. (Annual) New admirabilis). York State Mus. Nat. Hist. 24: 64. 1872. Type citation: “Old logs in woods. Greig. September.” Singer, Trans. Brit. Mycol. Soc. 39: 195; Smith ≡ Pluteus admirabilis (Peck) Peck, Rep. and Stuntz, Lloydia 21: 118. 1958; Banerjee and (Annual) New York State Mus. Nat. Hist. 38: 137. Sundberg, Mycotaxon 49: 416-418, Icon. 416-417, 1885. Fig. 4. 1993a (as Pluteus aurantiacus). = Pluteus aurantiacus Murrill, North American Flora 10: 129. 1917. Type citation: “Type Pegler, Agaric Flora of the Lesser Antilles: 324- collected on decayed wood among mosses in 325, Icon. 326, Fig. 61, L-Q. 1983. (as Pluteus swampy ground at West Park, New York, August chrysophlebius). 1, 1903, F. S. Earle 1664 (herb. N. Y. Bot. Gard.).” = Pluteus melleus Murrill, North American Flora Singer, Trans. Brit. Mycol. Soc. 39: 176; Smith 10: 129. 1917. Type citation: “Type collected on and Stuntz, Lloydia 21: 129. 1958; Banerjee and Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 23

Sundberg, Mycotaxon 49: 424-426, Icon. 424- lacking apparent intracellular pigment. Pileus 425, Fig. 22. 1993a (as Pluteus melleus). trama septate, hyaline. Stipitipellis a cutis of cylindrical hyphae, 3–19 μm wide, walls thin and Singer, Trans. Brit. Mycol. Soc. 39: 213. 1956; hyaline in KOH, septate, without apparent Smith and Stuntz, Lloydia 21: 134. 1958; Homola, contents. Clamp connections absent. A Systematic Study of the Section Celluloderma Fayod of the Genus Pluteus Fries in North Agaricus admirabilis (original material) America, 121-127, Icon. 122-123, Pl. XII, Figs. 1-6. 1969; Homola, Mycologia 64: 1240-1241. 1972; Basidiocarps 1.5–2' (3.8–5 cm) high. Pileus 6– Banerjee and Sundberg, Mycotaxon 49: 432, 10'' (1.3–2.1 cm) in diameter, convex, broadly Icon. 430-431, Fig. 34. 1993a (as Pluteus umbonate; surface glabrous, rugose-reticulate, rugosidiscus). hygrophanous; bright yellow; margin obscurely striate when moist, thin. Stipe up to 1'' (2.1 mm) Description of the type specimens: thick, equal to slightly thickened at the base; Agaricus chrysophlebius (lectotype) surface smooth; yellow; hollow; basal mycelium white. Lamellae remote, broad, close, dull yellow Pileus 1.1 cm in diameter, convex; disc with becoming flesh colored. radiating reticulate veins; smoky yellow. Stipe 2.2–4.4 cm in length, enlarged above; base Neither the original collection at NYS or the bulbous, white, hirsute. Lamellae remote, broad, possible one at NY (see notes) were examined for white becoming flesh-colored. microscopic morphological characters. See Singer (1956) and Banerjee and Sundberg Basidiospores 5.3–7.9 × 4.8–7.0 μm, Q = 1.00– (1993a) for descriptions and illustrations 1.29 (Lm = 6.8 μm, Wm = 6.1 μm, Qm = 1.12), (Banerjee and Sundberg 1993a) of these globose, subglobose to broadly ellipsoid to rarely characters from the original specimens. Homola inequilateral in face and profile views, circular in (1969, 1972) also studied original material, but he end views, apiculate, smooth, walls slightly did not separate data obtained from it and data thickened, subhyaline to pale yellow in KOH, from other collections. contents often of one to several scattered oil drops and appearing grainy. Basidia 20–32 × 6– Pluteus aurantiacus (holotype) 11 μm, clavate, tetrasterigmate, walls thin and hyaline in KOH, usually lacking apparent Pileus 2 cm in diameter, convex, not fully contents. Pleurocystidia 44–67 × 12–22 μm, not expanded, umbonate; surface glabrous, rugose; uncommon, more or less lageniform with deep-orange-yellow; margin entire, striate. Stipe pedicels and short to moderately long necks with 4–5 cm x 2 mm, equal; surface glabrous, shining; usually narrow, obtuse apices, walls thin and pale yellow; fragile, hollow. Lamellae free, rather hyaline in KOH, lacking visible intracellular broad, sub-crowded, pallid becoming salmon contents, at times covered with amorphous, colored; edges entire and concolorous. mucilaginous material. Cheilocystidia 24–41 × 13–18 μm, infrequent, fasciculate, Basidiospores 5.7–7.9 × 4.8–7.0 μm, Q = 1.00– sphaeropedunculate to pyriform to lageniform, 1.33 (Lm = 6.6 μm, Wm = 5.9 μm, Qm = 1.13), walls thin and hyaline in KOH, without apparent subglobose, ovate, broadly ellipsoid, ellipsoid to contents. Lamellar trama hyaline. Pileipellis a rarely inequilateral in face and profile views, cystoderm, cells 23–42 × 12–42 μm, globose to circular in end views, apiculate, smooth, walls sphaeropedunculate to pyriform and with or slightly thickened, subhyaline to pale yellow in without pedicels, walls thin and hyaline in KOH, KOH, contents not visible or of one to many 24 Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 scattered guttules sometimes giving grainy apiculate, smooth, walls somewhat thickened, appearances. Basidia 17–22 × 8–10 μm, clavate, subhyaline to pale yellow in KOH, contents at tetrasterigmate, walls thin and hyaline in KOH, times uniguttulate or with sprinkled smaller contents granular to with no apparent contents. guttules giving grainy appearances. Basidia 13– Pleurocystidia 39–61 × 15–23 μm, scattered, 25 × 6–11 μm, squat-clavate, tetrasterigmate, cell common in abundance, lageniform with pedicels walls thin and hyaline in KOH, with granular and short to moderately long necks having obtuse contents or no apparent contents. Pleurocystidia apices to clavate, readily collapsing, walls thin 34–55 × 9–21 μm, moderately abundant, narrow and hyaline in KOH, lacking apparent to broadly lageniform having pedicels and long or intracellular contents, frequently covered with an short necks with obtuse apices or short mucros, apical cap of amorphous, mucilaginous material. often collapsing, walls thin and hyaline in KOH, Cheilocystidia 28–50 × 12–17 μm, few seen due no apparent contents, frequently covered with a to poor revival of hymenium, clavate to cap of amorphous, mucilaginous material. lageniform with pedicels and necks having obtuse Cheilocystidia 31–46 × 10–18 μm, rare to apices, readily collapsing, walls thin and hyaline infrequent, sphaeropedunculate to pyriform, in KOH, lacking apparent contents, sometimes walls thin and hyaline in KOH, without apparent covered with an apical cap of amorphous, contents, at times covered with an apical mucilaginous material. Lamellar trama hyaline. mucilage cap. Lamellar trama hyaline. Pileipellis Pileipellis a cystoderm, cells 21–33 × 18–22 μm, a cystoderm, cells 24–33 × 11–28 μm, mostly globose to sphaeropedunculate to pyriform and sphaeropedunculate to pyriform, walls thin and pedicellate to apedicellate, walls thin and hyaline hyaline in KOH, contents hyaline or of light in KOH, contents hyaline. Pileus trama hyaline, fuscous intracellular pigment, cells adhering septate. Stipitipellis a cutis of cylindrical hyphae, strongly to each other. Pileus trama hyaline, 2–17 μm wide, walls thin and hyaline in KOH, septate. Stipitipellis a cutis of cylindrical hyphae, septate, without apparent contents. Clamp 3–26 μm wide, walls thin and hyaline in KOH, connections none. septate, no apparent contents. Clamp connections absent. The hymenium did not revive well in our slide preparations. Pluteus melleus (original material)

Pluteus melleus (holotype) Basidiospores 5.7–7.9 × 4.8–6.6 μm, Q = 1.00– 1.36 (Lm = 6.6 μm, Wm = 5.8 μm, Qm = 1.14), flesh Pileus 1–2 cm in diameter, convex becoming colored in mass, globose, subglobose, broadly subexpanded, umbonate; surface glabrous, ellipsoid, ellipsoid, ovate to slightly inequilateral rugose; pale-melleous with slightly darker umbo; in face and profile views, circular in end views, margin entire to undulate, concolorous. Stipe 2 apiculate, smooth, walls slightly thickened, cm x 1 mm, cylindrical, equal; surface smooth, subhyaline to pale yellow in KOH, contents not glabrous; pale melleous. Lamellae free, broad, visible or of one to many scattered guttules giving ventricose, crowded, inserted several times, white grainy appearances. Basidia 17–24 × 7–9 μm, becoming salmon colored; edges entire and clavate, tetrasterigmate, walls thin and hyaline in concolorous. KOH, containing granular contents or without visible contents. Pleurocystidia 44–72 × 15–23 Basidiospores 5.7–7.9 × 5.3–6.6 μm, Q = 1.00– μm, common, lageniform having pedicels and 1.31 (Lm = 6.7 μm, Wm = 5.9 μm, Qm = 1.14), short to long broad necks with relatively wide, globose, subglobose, broadly ellipsoid to ovate in obtuse apices, walls thin and hyaline in KOH, face and profile views, circular in end views, without apparent contents, often possessing a cap Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 25 of amorphous, mucilaginous material at the yellow, R) to tawny to (dark olive yellow, R) to apices. Cheilocystidia 24–44 × 11–18 μm, greenish, some with olive-brown hues towards common, pyriform to lageniform with pedicels margin; margin decurved becoming plane, entire, and necks having obtuse apices, walls thin and striate in age. Stipe 0.8–4.0 cm × 1–3 mm, equal hyaline in KOH, lacking discernable intracellular to tapering upwards at times with slightly contents, often with amorphous, mucilaginous bulbous base, straight to slightly curved; surface material at the apices. Lamellar trama hyaline. moist, glabrous; very pale yellow (cream color to Pileipellis a cystoderm, cells 17–39 × 10–26 μm, naples yellow, R) to yellow (amber yellow to globose to sphaeropedunculate to pyriform and straw yellow above and near wax yellow below, R; pedicellate or not with rare, short mucro at 3A7, M); solid to stuffed to hollow, basal apices, walls thin and hyaline in KOH, filled with tomentum white. Lamellae free, up to 4 mm very light brown intracellular pigment or having broad, ventricose, close, thin, fragile, white no visible contents, cells moderately adhering to becoming pinkish (light pinkish cinnamon, R); each other in crush mounts. Pileus trama edges smooth, white to yellowish becoming hyaline, septate. Stipitipellis a cutis of cylindrical pinkish. Lamellulae in 1–2 tiers. Context in hyphae, 3–21 μm wide, walls thin and hyaline in pileus up to 2 mm thick, white to light yellow, KOH, septate, without apparent contents. Clamp unchanging. Stipe context with white pith and connections absent. cortex more or less concolorous with surface. Odor not distinctive. Taste not distinctive. Spore Pluteus rugosidiscus (holotype) deposit rosy.

Pileus 1–1.5 cm in diameter, convex becoming Basidiospores 5.3–7.5 × 4.8–6.6 μm, Q = 1.00– subexpanded, slightly umbonate; surface 1.41 (Lm = 6.4 μm, Wm = 5.4 μm, Qm = 1.19), glabrous, moist; greenish yellow; disk with globose to subglobose to predominantly ovate, pruinose, reticulate, raised, radiating lines, broadly ellipsoid to ellipsoid in face and profile smoky-green; margin entire, concolorous, not views, circular in end views, apiculate, smooth, striate. Stipe 2.5 cm x 1 mm, cylindrical, equal; walls slightly thickened, subhyaline to pale yellow surface smooth, glabrous; greenish yellow; basal in KOH, contents not visible or of one to many tomentum white. Lamellae free, broad, scattered guttules. Basidia 15–38 × 5–10 μm, ventricose, crowded, inserted, white becoming- clavate, tetrasterigmate, walls thin and hyaline in salmon colored; edges entire and concolorous. KOH, contents granular to agranular. Pleurocystidia 35–94 × 11–29 μm, scattered, The holotype was not examined for microscopic common in abundance, lageniform with pedicels morphological characters because very little and short to moderately long necks having obtuse material remains. See Singer (1956), Smith and apices to clavate to rarely utriform, walls thin and Stuntz (1958), and Banerjee and Sundberg hyaline in KOH, lacking apparent intracellular (1993a) for descriptions of these characters from contents, at times covered with an apical cap of the type collection. amorphous, mucilaginous material. Cheilocystidia 25–61 × 7–22 μm, frequent to General description: Pileus 0.4–2.6 cm in crowded in abundance, globose to diameter, convex becoming plano-convex to sphaeropedunculate to pyriform to clavate to plane to rarely uplifted, some portions uplifted in subcylindrical to lageniform with pedicels and age, umbonate; surface moist, glabrous, dull, necks having obtuse apices, walls thin and rugulose, hygrophanous; yellow (light cadmium hyaline in KOH, lacking apparent contents, to near empire yellow, R; near 4B4–8 and 4C8, sometimes covered with an apical cap of M) and remaining so in age to darkening (aniline amorphous, mucilaginous material. Lamellar 26 Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 trama convergent, hyaline. Subhymenium 16 (SIU as Pluteus admirabilis). Johnson Co., cellular, hyaline. Pileipellis a cystoderm, cells near Vienna, Goose Pond Area, Little Black 17–44 × 12–29 μm, globose to Slough, scattered to near caespitose on sphaeropedunculate to pyriform to rarely decorticated hardwood, 25.IX.1976, coll. WJ irregularly lageniform with few having a short Sundberg, WJ Sundberg 4414 (SIU as Pluteus mucro and pedicellate to apedicellate, walls thin admirabilis). Union Co., gregarious on and hyaline in KOH, contents hyaline to decorticated deciduous wood, VI–VII.2003, coll. yellowish to very lightly dark pigmented with AM Minnis, Minnis SB2003 (SIU). KENTUCKY: olive to brown coloration. Pileus trama hyaline, Lyon Co., Land Between the Lakes, Moss Creek septate. Stipitipellis a cutis of cylindrical hyphae, Rd., solitary on small decorticated log, 11.V.1974, 3–22 μm wide, walls thin and hyaline in KOH, coll. Marcia Grady, WJ Sundberg 2669 (SIU as septate, without apparent contents. Clamp Pluteus sp.). LOUISIANA: Lafayette Parish, connections absent. Oleiferous hyphae present. along Vermillion River off New Flanders Road ca. Mi. 3 miles (5 km) south of Lafayette, in hardwood forest 23.VI.1974, coll. CM Allen, 5686 (LSU as Habit and habitat: Solitary to scattered to Pluteus leoninus). MICHIGAN: Alger Co., Rock gregarious on dead wood and woody debris. River, on Betula stick, 21.IX.1929, coll. AH Smith, AH Smith 72905 (MICH as Pluteus Material examined: U.S.A., CALIFORNIA: aurantiorugosus). Mackinaw Co., probably on San Mateo Co., San Francisco Watershed, deciduous wood, 07.VII.1965, coll. RL Homola, gregarious on dead Quercus log, 16.IV.1967, coll. RL Homola 1352 (MICH as Pluteus HD Thiers, HD Thiers 18841 (SFSU as Pluteus rugosidiscus). Montmorency Co., approximately rugosidiscus). IDAHO: scattered on hardwood 15 miles (24 km) east of Vanderbilt, growing on logs, 19.IX.1976, coll. WJ Sundberg, B Strack 6 rotten log in beech-maple woods, 15.VIII.1962, (SIU as Pluteus admirabilis). ILLINOIS: coll. RL Homola, RL Homola 109 (MICH as Jackson Co., Giant City State Park, gregarious on Pluteus rugosidiscus). Oakland Co., Pontiac, on dead Quercus log, 10.VI.1976, coll. HD Thiers, debris, 24.VI.1937, coll. AH Smith, AH Smith HD Thiers 36124 (SFSU as Pluteus admirabilis); 6404 (MICH as Pluteus rugosidiscus). Giant City State Park, Devil’s Stand, gregarious Tahquamenon State Park, Upper Falls, on decaying wood, 17.VI.1992, coll. T McCovery, 7.VII.1955, coll. B Lowy, B Lowy, s.n. (LSU as T McCovery 7 (SIU as Pluteus admirabilis); Pluteus admirabilis). MINNESOTA: Clearwater Little Grand Canyon, Shawnee National Forest, Co., Itasca State Park, on fallen Pinus strobus on 26.V.1973, coll. WJ Sundberg, WJ Sundberg 2221 Wilderness Drive, 05.VIII.1982, coll. R Sorensen, (SIU as Pluteus melleus); Little Grand Canyon, R Sorensen 58 (MIN as Pluteus admirabilis); near Murphysboro, gregarious on dead hardwood Itasca State Park, Bear Paw Point, 22.VII.1982, log, 09.VI.1976, coll. HD Thiers, HD Thiers 36101 coll. R Sorensen, R Sorensen 3 (MIN as Pluteus (SFSU as Pluteus admirabilis); near Makanda, rugosidiscus); 28.VII.1982, coll. R Sorensen, R Giant City State Park, Campground Area, Sorensen 36; R Sorensen 22 (MIN as Pluteus scattered to gregarious on well decomposed log, admirabilis); Itasca State Park, Schoolcraft Trail, 10.VI.1976, coll. WJ Sundberg, WJ Sundberg 04.VIII.1979, coll. MW Andrews, MW Andrews 3276 (SIU as Pluteus admirabilis); near Pomona, 64 (MIN as Pluteus admirabilis). Hubbard Co., Pomona Natural Bridge, scattered near surface of Itasca State Park, service road opposite Forestry ground on decaying hardwood logs, 01.VII.1992, and Biology Station, 26.VII.1982, coll. R coll. MA Basinger, MA Basinger 66 (SIU as Sorensen, R Sorensen 17 (MIN as Pluteus Pluteus admirabilis); scattered on lignicolous admirabilis). Isanti Co., Collection Area N, Sect. substrate, 01.VII.1992, coll. S Klavins, S Klavins 21, Athens Twp., north of Firebreak Rd., Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 27 gregarious on log in mixed woods predominantly HW Ravenel, s.n. (lectotype of Agaricus of Quercus, Betula papyrifera, and Pinus chrysophlebius, FH); HW Ravenel, s.n. (K(M) strobus, 24.VII.1968, coll. MG Weaver, MG 39265) (duplicate of lectotype of Agaricus Weaver 1610 (MIN). Stearns Co., St. Joseph, chrysophlebius, K). TENNESSEE: Unaka larch swamp east of Partch Woods, on dead Springs, mixed woods with evergreens wood, 06.VII.2001, coll. Sean Westmoreland, predominating at 1700 ft (518 m) elevation, 18- NAMA 2001-097 (MIN as Pluteus admirabilis). 24.VIII.1904, coll. WA Murrill, WA Murrill 840 MISSOURI: Howell Co., scattered on wood, (holotype of Pluteus melleus, NY). VIRGINIA: 14.VI.2007, coll. B McDermith, B McDermith, Falls Church, in deciduous woods, 2-6.VII.1904, s.n. (UMO). Wayne Co., near Puxico, Mingo coll. WA Murrill, WA Murrill 111 (holotype of National Wildlife Refuge, scattered on Pluteus rugosidiscus, NY). decorticated deciduous wood, 19.IX.2003, coll. AM Minnis, Minnis 3-09-19-17 (SIU); Known distribution: Pluteus chrysophlebius 20.IX.2003, coll. MOMS members, Minnis 3-09- var. chrysophlebius is widely distributed in the 20-5 (SIU); Minnis 3-09-20-7 (SIU); 16.IX.2006, U.S.A. It has also been reported from the coll. J Justice, Minnis 6-09-16-5 (SIU). NEW Caribbean (Pegler 1983) and Mexico (Rodríguez YORK: Lewis Co. Greig, VII & IX, coll. CH Peck, and Guzmán-Dávalos 1999, 2001). Several other CH Peck, s.n. (original material of Agaricus subspecies and varieties of Pluteus admirabilis, NYS); Grieg, VIII.1870, coll. CH chrysophlebius have been reported from South Peck, CH Peck, s.n. (original material of Agaricus America (Singer 1958). admirabilis?, NY). Lake Placid, Adirondacks, coniferous or mixed forest at 2000 ft (610 m) Notes: The macromorphological descriptions of elevation, 17-29.VII.1912, coll. WA Murrill and the type collections of Agaricus chrysophlebius, EL Murrill, WA Murrill and EL Murrill 206 Agaricus admirabilis, and Pluteus aurantiacus, (original material of Pluteus melleus, NY). West Pluteus melleus, and Pluteus rugosidiscus were Park, on decayed wood among mosses in swampy adapted from the protologues by Berkeley and ground, 01.VIII.1903. coll. FS Earle, FS Earle Ravenel (Berkeley and Curtis 1859), Peck (1872), 1664 (holotype of Pluteus aurantiacus, NY). and Murrill (1917), respectively. The protologue NORTH CAROLINA: Haywood Co., Great Smoky for Agaricus chrysophlebius does not cite a Mountains National Park, Cataloochee, specific specimen and only gives scant collection 11.VII.1988, coll. DE Desjardin, DE Desjardin data. Two presumed duplicates of a gathering 4568 (SFSU). OHIO: Columbiana Co., St. Clair used to circumscribe the taxon are located in Twp. Sprucevale Area, Beaver Creek State Park, separate herbaria. Singer (1956) designated the Voucher for Ohio Mushroom Society Foray, collection located at Ravenel’s herbarium as the 02.X.1993, MA Vincent and OMS Foray lectotype. We were only able to study photocopy Participants, 6390 (MU as Pluteus admirabilis). images of the duplicate of the lectotype, but Greene Co., near Xenia, Robert Morton DDS, on Pegler (1983) and Rodríguez and Guzmán– rotting wood, 13.X.1970, coll. WB and VG Cooke, Dávalos (2001) have studied it more thoroughly 43767 (MU as Pluteus leoninus). Preble Co., and apply the taxon as we have. The protologue Hueston’s Woods State Park, on Fagus log, for Agaricus admirabilis does not cite a specific 03.X.1970, coll. WB and VG Cooke, 43653 (MU type specimen and only provides limited as Pluteus leoninus); Hueston’s Woods State collection data. Two possible duplicates of the Park, Big Woods Area, on rotten Acer nigrum same collection that Peck used to describe the log, 27.IX.1969, WB and VG Cooke, 41524 (MU species are found in separate herbaria. Singer as Pluteus admirabilis). SOUTH CAROLINA: ad (1956) pointed out that one housed at NYS trunc. putr. Carya, IX.1852, coll. HW Ravenel, consists of specimens collected on different days. 28 Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107

According to the ICBN Art. 8.2 (McNeill et al. and Guzmán-Dávalos (2001) studied various 2006), this is not an acceptable type. The collections from North America as well as P. specimen located at NY has some potential chrysophlebius type material. Both considered mistakes on the specimen labeled “portion of type all of the collections including some identified as collection”. Greig is misspelled Grieg and the P. admirabilis to be conspecific with P. month is August (it should be September chrysophlebius and listed P. admirabilis as a according to the protologue). This specimen may synonym of P. chrysophlebius. We have or may not be a duplicate of the material at NYS. examined original material for both taxa, and the Since there is some doubt as to whether Peck two are certainly the same. Although P. used this latter specimen to describe Agaricus admirabilis is prevalent in popular field guides, admirabilis and whether it is suitable as a type, P. chrysophlebius must be used. Insufficient especially if it is a mixed collection, an original descriptions as well as a failure to illustration of a September collection made by examine type material from both taxa and Peck is designated as the lectotype. The other ignoring previous taxonomic studies led to the specimens cited previously as types in other long standing taxonomic confusion about these works are listed under original material. One two epithets. authentic collection of P. melleus indirectly mentioned in the protologue (Murrill 1917), but Singer (1956), based on his study of the holotypes not listed as a type, was presented separately of two species, considered P. aurantiacus to be because the holotype is in poor condition an obvious synonym of Pluteus aurantiorugosus consisting of a fragment of the pileus with (Trog) Sacc. Smith and Stuntz (1958), based on associated stipe. This original material may be examination of the holotype of P. aurantiacus, used as a future type if the current holotype is no disagreed and cited spore size and stipe longer able to serve as a type. coloration in their argument against synonymy as they implied a close relationship with P. Pluteus chrysophlebius has priority over Pluteus admirabilis. In their re-examination of the admirabilis. The latter name is commonly found Pluteus aurantiacus holotype, Banerjee and in popular literature on fungi in the U.S.A. Sundberg (1993a) believed the basidiospore size Pluteus chrysophlebius was described by and stipe coloration of P. aurantiacus to be Berkeley and Ravenel in Berkeley and Curtis similar to P. aurantiorugosus. However, color (1859) from scant notes and dried specimens sent differences in the pileus and the implied lack of from Ravenel. Peck (1872) described P. cottony mycelium at the stipe base in P. admirabilis as new and believed it differed from aurantiacus (in the first author’s experience, a P. chrysophlebius in the possession of a variable character in P. aurantiorugosus) left hygrophanous pileus, yellow lamellae, and yellow them uncertain about the question of synonymy. stipe. None of these characters were described The examination of the holotype of P. well in the original notes from Ravenel at the aurantiacus revealed the absence of oblong Royal Botanic Gardens in Kew (K) which merely basidiospores that are characteristic of every P. state the base of the stipe was white. Murrill aurantiorugosus collection that was examined. (1917) thought that the two species may be the This basidiospore shape has also been shown in same. Singer (1956) based on his examination of European material by Vellinga (1990). material from both taxa believed the two to be Additionally, the deep-orange-yellow coloration synonymous. Homola (1969, 1972) did not study of the pileus of P. aurantiacus as described in the type material from P. chrysophlebius and protologue is not indicative of the more scarlet considered the taxa to be distinct based on the hues of P. aurantiorugosus and suggests yellow short diagnoses. Pegler (1983) and Rodríguez was the primary color of the pileal surface. In the Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 29 field the first author has seen dark orange-yellow brownish hue at times in age. Intermediate to colorations on the pileus of specimens of the this darker shade, greenish-yellow hues are hygrophanous P. chrysophlebius, an observation common. The first author has also noticed that shared by Homola (1969, 1972) in his description the basidiocarps dry lighter or darker depending of P. admirabilis. There is little doubt that P. on their state and drying conditions. Study of the aurantiacus is a synonym of P. chrysophlebius. cuticle of numerous collections has revealed a range of coloration in the cells of the pileipellis Based on examination of type material, Pluteus from hyaline to yellowish to olive to slightly melleus is another synonym of Pluteus brownish. For these reasons, Pluteus chrysophlebius. Murrill (1917) probably rugosidiscus is treated herein as a synonym of described this species as distinct based on its Pluteus chrysophlebius. slightly darker umbo. Again, color is quite variable in this hygrophanous species and Singer (1958) recognized a number of varieties nothing distinctive can be found to differentiate and subspecies of P. chrysophlebius based on the holotype from other P. chrysophlebius spore size, spore shape, and degree of wrinkling material. Singer (1956) classified P. melleus in on the pileus surface. Many are from South section Hispidoderma. Smith and Stuntz (1958) America (Singer 1958). These taxa included and Banerjee and Sundberg (1993a) considered Pluteus chrysophlebius subspecies P. melleus as a possible synonym or a slight color chrysophlebius, Pluteus chrysophlebius variant of P. admirabilis and also a member of subspecies sublaevigatus Singer, Pluteus section Celluloderma. Homola (1969, 1972) did chrysophlebius subspecies bruchii (Speg.) Singer not study the type of P. melleus and referred to var. bruchii, and Pluteus chrysophlebius Smith and Stuntz (1958) in a discussion of subspecies bruchii var. aconquijensis Singer ad synonymy, color variants, and questionable taxa. int. (Singer 1958). No subsequent taxonomic study has sufficiently addressed these South Pluteus rugosidiscus has a long tradition of being American taxa. considered a good species due to the greenish hues in the pileus (Murrill 1917, Singer 1956, No other North American taxa possess the Smith and Stuntz 1958, Homola 1969, 1972; combination of a yellowish colored pileus and Banerjee and Sundberg 1993a). Homola (1969, stipe and cellular pileipellis. Pluteus 1972) and Banerjee and Sundberg (1993a) flavofuligineus G.F. Atk. from North America has considered it to be closely related to Pluteus a similar pileus coloration. It differs from P. admirabilis, a later synonym of Pluteus chrysophlebius var. chrysophlebius in having a chrysophlebius. Homola (1969, 1972) believed whitish colored stipe and a filamentous that the two species were microscopically pileipellis. The European Pluteus chrysophaeus indistinguishable except for the presence of a (Schaeff. : Fr.) Quél. sensu Vellinga (1990) and its slightly dark intracellular pigment in P. synonyms such as Pluteus luteovirens Rea, rugosidiscus and the lack of it in P. admirabilis. Pluteus galeroides P.D. Orton, and Pluteus However, Singer (1956), Smith and Stuntz xanthophaeus P.D. Orton which are differently (1958), and Banerjee and Sundberg (1993a) all classified by Orton (1986) and Vellinga (1990) noticed in their study of the holotype that the are comparable. Pluteus luteostipitatus C.K. cells of the pileipellis lack any sort of dark Pradeep & K.B. Vrinda described from India pigmentation. (Pradeep and Vrinda 2008) differs in part by its large clavate, vesiculose pleurocystidia. Future In our observations of Pluteus chrysophlebius, research should address the possible synonymy the pileus is hygrophanous and tends to turn a 30 Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 of these species with each other and P. mm broad, ventricose, rounded at margin, not chrysophlebius. forked, pale pinkish becoming pale reddish (9A2, M); edges more or less concolorous, uneven in In conclusion, P. chrysophlebius var. places. Lamellulae in 3 tiers. Context in pileus chrysophlebius is the correct name for a whitish, unchanging, far more abundant at disc collection of several synonyms. The confusion than margin. Stipe context whitish, bluish gray at relating to these names is due to color variation base (16D1-16E1, M). Spore print rosy. of this species and incomplete to vague protologues. Future work should utilize DNA Basidiospores 6.2–8.8 × 5.3–7.5 μm, Q = 1.00– data as well as mating studies to determine if 1.33 (Lm = 7.1 μm, Wm = 6.2 μm, Qm = 1.15), few regional isolates are distinct from each other. globose to subglobose to predominantly broadly ellipsoid to ovate in face and profile views, circular in end views, apiculate, smooth, walls (8) Pluteus cyanopus Quél., Assoc. Franç. slightly thickened, subhyaline to pale yellow in Avancem. Sci. Conf. 11: 391. 1882. Type citation: KOH, contents not visible or of one to few “Sur les brindilles et les souches des forêts guttules. Basidia 20–43 × 8–11 μm, clavate, ombragées du Jura. Voisine de phlebophorus.” tetrasterigmate, walls thin and hyaline in KOH, Fig. 21. with granular contents or agranular. Pleurocystidia 39–75 × 17–33 μm, scattered, Types and typifications: No type exists. See common in abundance, utriform to broadly discussion below. lageniform with pedicels and short necks having obtuse apices, walls thin and hyaline in KOH, Diagnostic characters: Pileus dark brown; lacking visible intracellular contents, rarely stipe whitish with bluish to gray colorations at covered by apical caps of amorphous, the base. Microscopically, pleurocystidia broadly mucilaginous material. Cheilocystidia 33–51 × lageniform to utriform; hyaline; pileipellis 17–28 μm, crowded, pyriform to clavate to lacking cystidioid elements. lageniform to utriform, walls thin and hyaline in KOH, lacking apparent contents, rarely covered Selected descriptions and illustrations: by apical caps of amorphous, mucilaginous Vellinga, Pluteus, In: Bas et al., Flora Agaracina material. Lamellar trama hyaline, septate. Neerlandica, Vol. 2, 53, Icon. 53, Fig. 34. 1990. Pileipellis a cystoderm, cells 28–44 × 12–19 μm, globose to sphaeropedunculate to pyriform to General description: Pileus up to 2 cm in rarely irregularly clavate and pedicellate to diameter, convex-conic becoming expanded- apedicellate, walls thin and hyaline in KOH, filled convex to plane, subumbonate; surface dry, dull, with brown intracellular pigment, cells velvety under hand lens; dark brown (6E7, M) moderately adhering to one another in crush with paler margin becoming more or less mounts. Context in pileus hyaline, septate. uniformly dark brown (6E6–6F6, M); margin Stipitipellis a cutis of cylindrical hyphae, 3–24 incurved becoming decurved, indistinctly μm wide, walls thin and hyaline in KOH, septate, translucent-striate, entire then becoming rimose. without apparent contents. Clamp connections Stipe up to 2.9 cm × 4 mm, tapering downward to absent. Oleiferous hyphae present. midportion and then enlarging to base, straight or slightly curved twisted, split longitudinally in age; surface fibrillose-striate; whitish with base Habit and habitat: Gregarious on roots and bluish gray (25B2, M) becoming grayish humus at base of tree in mixed forest mostly of translucent (20C1, M). Lamellae free, up to 4 Acer, Fraxinus, Quercus, and Tilia. Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 31

Material examined: U.S.A., MINNESOTA: lacks the bluish hues at the stipe base. Pluteus Rice Co., Nerstrand Woods State Park, Section 9, phaeocyanopus differs from P. cyanopus in that Wheeling Township., gregarious on roots and the former possesses brown pigmented cystidia humus, 22.VII.1967, coll. WG Weaver, MG and pleurocystidia that are more narrowly Weaver 1430 (MIN as Pluteus nanus?). lageniform than the broadly lageniform to utriform pleurocystidia of P. cyanopus. Pluteus Known distribution: Pluteus cyanopus occurs salicinus (Pers. : Fr.) P. Kumm., a not uncommon in Europe and Africa (Vellinga 1990). Homola species in the U.S.A. with a bluish staining stipe, (1972) reported its occurrence in the U.S.A. in belongs to section Pluteus and is easily California, Michigan, and Wyoming. It is herein distinguished by its filamentous cuticle and reported from Minnesota, U.S.A. metuloid, horned pleurocystidia. Pluteus leucocyanescens Singer, a Mexican taxon, also Notes: The topotype for this species is in France has a bluish staining stipe, but it differs in part by (Quélet 1882). Based on available resources, we the possession of a filamentous cuticle and thin- are not aware of any type material for this fungus. walled cystidia, characters that place it in section We believe European workers should select an Hispidoderma. appropriate specimen from the type locality to serve as a type. Vellinga and Schreurs (1985) Pluteus cyanopus remains a poorly known have synonymized P. cyanopus with the invalidly species in the U.S.A. and more collections with published Pluteus metrodii Malençon & Bertault, quality notes on fresh material are needed in another European taxon that differs in stipe hue order to gain a better understanding of this and cystidial shape, because of the variation they species and its distribution. Genetic studies observed in cystidial shape and stipe coloration. should also be performed to determine whether or not it is distinct from European populations. The collection we observed fits well with the interpretation of Pluteus cyanopus presented by (9) Pluteus deceptivus Minnis & Sundb., sp. Vellinga (1990). Homola (1969, 1972) nov. Fig. 22. documented this species in three states. The Mycobank: 512856 material studied by Homola from California that we examined appears to belong to a different Etymology: Named after the difficulty both species, Pluteus phaeocyanopus Minnis & historical and in practice of identifying this Sundb., which is discussed below. We have not fungus. confirmed the identifications of other collections seen by Homola (1969, 1972). Latin diagnosis: Pileus atrocolor, demum asterorimosus. Stipites pallentes. Homola (1969) believed that the only way to Pleurocystidia late ventricosa fusiformia vel distinguish P. cyanopus from Pluteus subcylindracea. Pileipellis cellulosa; cellulae phlebophorus (Ditmar : Fr.) P. Kumm. (as variae forma et amplitudine, aliquot relative Pluteus chrysophaeus (Schaeff. : Fr.) Quél. sensu amplae. Pilocystidia carentia. Homola) in the herbarium was a slight bluish tint on the stipe. The first author was unable to Holotype: U.S.A., MICHIGAN: Washtenaw Co., observe this character, and it was concluded that Dexter, on debris of low wet woods around it probably fades as the dried material ages. rotting logs of Tilia glabra, 14.VIII.1942, coll. AH However, P. phlebophorus appears to differ by Smith, AH Smith 18670 (MICH). the possession of some narrowly lageniform pleurocystidia with long necks and when fresh 32 Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107

Diagnostic characters: Macroscopically, hyaline in KOH, with or without granular pileus brownish; becoming conspicuously contents. Pleurocystidia 44–55 × 15–26 μm, radiately rimose in age; stipe pale colored. infrequent in abundance, either lageniform to Microscopically, pleurocystidia few; usually utriform with pedicels and with short necks broadly lageniform to utriform to subcylindrical having moderately broad, obtuse apices or sub- in shape; pileipellis elements variable in size and cylindrical with slightly greater width at shape with some relatively large (> 60 × > 40 approximately 1/2 the length of the cell , walls μm); pileipellis lacking cystidioid elements. thin and hyaline in KOH, no apparent contents, occasionally covered with an apical cap of Selected descriptions and illustrations: amorphous, mucilaginous material. Homola, A Systematic Study of the Section Cheilocystidia 33–55 × 12–23 μm, crowded, Celluloderma Fayod of the Genus Pluteus Fries in narrowly to broadly lageniform with distinct North America, 89-98, Icon. 90-91, Pl. VII, Figs. pedicels and with short necks having narrow to 1-4. 1969. broad breadth and obtuse apices to more or less clavate to ellipsoid, walls thin and hyaline in Homola, Mycologia 64: 1229-1231. 1972 (as KOH, lacking apparent contents, often covered Pluteus sp.). with an apical cap of amorphous, mucilaginous material. Lamellar trama convergent, hyaline. Description of the type specimens: Subhymenium cellular, hyaline. Pileipellis a cystoderm, cells 34–90 × 24–66 μm, mostly Pileus 3–6.5 cm in diameter, obtuse to convex subglobose to pyriform with few irregular in becoming broadly convex to nearly plane; surface shape, walls thin and hyaline in KOH, containing dry, glabrous, disc smooth or rugulose, becoming brown intracellular pigment. Pileus trama conspicuously radiately rimose from margin hyaline, septate. Stipitipellis a cutis of cylindrical inward in age; blackish brown (fuscous, R) on hyphae, 3–23 μm wide, walls thin and hyaline in disc and gray to avellaneous (drab to avellaneous, KOH, septate, no apparent contents. Clamp R) towards the margin; ground color showing connections absent. Oleiferous hyphae present. through split cuticle pallid to pinkish; margin Mi. often plicate in age. Stipe 4–8 cm x 3–6 mm, equal; surface glabrous, innately striate; white to Habit and habitat: Scattered on debris in very pale straw colored; solid; firm. Lamellae association with decayed logs of Tilia glabra. free, broad, moderately close to subdistant, pallid to whitish becoming pink; edges smooth to finely Material examined: U.S.A., MICHIGAN: fimbriate, concolorous. Lamellulae 1–2 tiers. Washtenaw Co., Dexter, on debris of low wet Context thin, fragile, whitish. Odor mild. Taste woods around rotting logs of Tilia glabra, mild. 14.VIII.1942, coll. AH Smith, AH Smith 18670 (holotype of Pluteus deceptivus, MICH) Basidiospores 5.7–7.9 × 5.3–7.5 μm, Q = 1.00– 1.31 (Lm = 6.8 μm, Wm = 6.1 μm, Qm = 1.12), Known distribution: Pluteus deceptivus is globose, subglobose, broadly ellipsoid to ovate in known from Michigan, U.S.A. face and profile views, circular in end views, apiculate, smooth, walls slightly thickened, Notes: The macromorphological description was subhyaline to pale yellow in KOH, contents a adapted from Alexander H. Smith’s unpublished single large oil drop or scattered smaller drops notes (MICH) and Homola (1969, 1972). Smith giving grainy appearances. Basidia 22–33 × 8–11 recognized this taxon as a new species which he μm, clavate, tetrasterigmate, walls thin and named Pluteus rimosus. However, the name Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 33

Pluteus rimosus Murrill is already in use (Murrill is acceptable to publish this extremely rare 1911). Smith never published any data on this species as new. Any information will increase species. Homola (1969) examined the Smith awareness among mycologists and facilitate material and used the name Pluteus deceptivus future study. for this taxon in his dissertation. Homola never validly published this epithet and reported data (10) Pluteus fulvibadius Murrill, North for this taxon under Pluteus sp. (Homola 1972). American Flora 10: 136. 1917. Type citation: This taxon appears to be distinct. However, a “Type collected on the ground in woods at Glen second collection, AH Smith 47235, cited by Brook, Oregon, November 7, 1911, W. A. Murrill Homola (1969, 1972) appears to represent a 760 (herb. N. Y. Bot. Gard.).” Figs. 23–26. different fungus. The identity of this second = Pluteus melleipes Murrill, North American collection is unknown in part because the Flora 10: 129. 1917. Type citation: “Type accompanying notes were not sufficient. collected on rotten wood at West Park, New York, July 30, 1903, F. S. Earle 1589 (herb. N. Y. Bot. The European Pluteus rimulosus Kühner & Gard.).” Romagn. is similar in appearance but is distinguished from P. deceptivus by its lack of Diagnostic characters: Pileus brownish pleurocystidia (Homola 1969). The Jamaican colored; stipe yellowish. Microscopically, Pluteus rimosus Murrill, based on data presented pleurocystidia typically broadly lageniform to by Smith and Stuntz (1958) and Banerjee and utriform to cylindrical/clavate; basidiospores Sundberg (1993a), differs in having smaller ovate to broadly ellipsoid; pileipellis lacking spores. Pluteus rimosoaffinus Singer possesses cystidioid elements. darkly colored lamellar edges (Singer 1956), a character that P. deceptivus lacks. Pluteus Selected descriptions and illustrations: longistriatus (Peck) Peck, a common U.S.A. Singer, Trans. Brit. Mycol. Soc. 39: 199. 1956; species, has a pileus that is significantly less firm Smith and Stuntz, Lloydia 21: 122-123. 1958; (Smith’s unpublished notes, MICH) and a Banerjee and Sundberg, Mycotaxon 49: 420, pileipellis composed of filamentous elements Icon. 422-423, Fig. 13. 1993a (as Pluteus rather the than cellular elements found in P. fulvibadius). deceptivus. Homola (1969, 1972) noted that occasionally rimose basidiocarps of Pluteus Singer, Trans. Brit. Mycol. Soc. 39: 205. 1956; chrysophaeus (Schaeff. : Fr.) Quél. (see Pluteus Smith and Stuntz, Lloydia 21: 128-129. 1958; phlebophorus (Ditmar : Fr.) P. Kumm.) resulting Banerjee and Sundberg, Mycotaxon 49: 424-425, from certain environmental conditions may be Icon. 417, Fig. 21. 1993a (as Pluteus melleipes). confused with P. deceptivus. In such cases, the taxa are easily separated by pleurocystidial shape Homola, A Systematic Study of the Section (Homola 1969, 1972) with P. deceptivus typically Celluloderma Fayod of the Genus Pluteus Fries in lacking a slender lageniform shape having a long, North America, 129-134, Icon. 130-131, Pl. XIII, narrow neck. Pluteus fulvibadius Murrill is Figs. 1-5. 1969; Homola, Mycologia 64: 1243- somewhat similar and may also become areolate 1244, Icon. 1212, Fig. 8). 1972 (as Pluteus to rimose in age upon exposure to environmental lutescens var. lutescens). conditions, but P. deceptivus generally has a paler colored stipe and larger pileipellis elements. Homola, A Systematic Study of the Section Celluloderma Fayod of the Genus Pluteus Fries in Although many more collections are needed in North America, 134-139, Icon. 135-136, Pl. XIV, order to fully understand this taxon, we believe it 34 Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107

Figs. 1-5. 1969 (as Pluteus lutescens var. with an apical cap of amorphous, mucilaginous americanus). material. Lamellar trama hyaline. Pileipellis a cystoderm, cells 20–34 × 11–23 μm, globose to Homola, Mycologia 64: 1244-1246, Icon. 1223, sphaeropedunculate to short-clavate and Fig. 12. 1972 (as Pluteus lutescens var. sp.). pedicellate, walls thin and hyaline in KOH, containing dark brown intracellular pigment, Description of the type specimens: cells tightly adhering to one another in crush Pluteus fulvibadius (holotype) mounts. Pileus trama hyaline, septate. Stipitipellis a cutis of cylindrical hyphae, Pileus 5 cm in diameter, conic becoming elements 3–19 μm wide, walls thin and hyaline in campanulate, not fully expanded, umbonate; KOH, septate, without apparent contents. Clamp surface hygrophanous, glabrous, disc rugose- connections absent. radiate or reticulate-rugose; fulvous-badious, umbo castaneous; margin not striate, Pluteus melleipes (holotype) concolorous, splitting with age. Stipe 9 cm x 1 cm, subequal; surface glabrous, longitudinally Pileus 1–2.5 cm in diameter, broadly convex striate; citrinous; hollow; fleshy. Lamellae free becoming expanded, obtuse; surface (very close to stipe), not very broad, ventricose, hygrophanous, glabrous, rugose; cinnamon, citrinous becoming salmon colored; edges entire ochraceous dried; margin not striate. Stipe 2–4 and white. cm x 2mm, cylindrical, surface glabrous; honey yellow. Lamellae free, ventricose, crowded, white Basidiospores 5.7–7.0 × 5.3–7.0 μm, Q = 0.93– becoming brownish pink. 1.17 (Lm = 6.6 μm, Wm = 6.2 μm, Qm = 1.07), very few globose to typically subglobose, broadly Basidiospores 5.7–8.4 × 5.3–7.0 μm, Q = 0.87– ellipsoid to ovate in face and profile views, 1.29 (Lm = 6.7 μm, Wm = 6.1 μm, Qm = 1.11), circular in end views, apiculate, smooth, walls globose, subglobose, broadly ellipsoid to ovate in slightly thickened, subhyaline to pale yellow in face and profile views, circular in end views, KOH, contents not visible or of scattered guttules apiculate, smooth, walls slightly thickened, giving grainy appearances. Basidia 22–37 × 7–9 subhyaline to pale yellow in KOH, contents of one μm, clavate, tetrasterigmate, walls thin and to several scattered oil drops. Basidia 13–32 × 6– hyaline in KOH, contents granular to agranular. 10 μm, clavate, tetrasterigmate, walls thin and Pleurocystidia 28–76 × 15–35 μm, common in hyaline in KOH, usually lacking apparent abundance, predominantly cylindrical-clavate contents. Pleurocystidia 39–64 × 13–24 μm, not with pedicels and broad, obtuse apices to broadly uncommon, broadly lageniform with pedicels and lageniform to utriform having pedicels and short usually short necks with broad, obtuse apices to necks with broad, obtuse apices, usually broadly clavate to more or less cylindrical, walls collapsing, walls thin and hyaline in KOH, thin and hyaline in KOH, no apparent contents. lacking apparent intracellular contents, some Cheilocystidia 32–55 × 11–21 μm, broadly covered with an apical cap of amorphous, lageniform to utriform with pedicels and usually mucilaginous material. Cheilocystidia 35–64 × short necks with broad, obtuse apices to clavate 15–29 μm, crowded, globose to pyriform to to more or less cylindrical, walls thin and light cylindrical-clavate to broadly lageniform with colored in KOH, without visible contents. pedicels and short necks possessing broad, Lamellar trama hyaline. Pileipellis a cystoderm, obtuse apices, regularly collapsing, walls thin and cells 21–44 × 12–23 μm, mostly more or less hyaline in KOH, lacking apparent contents or globose to sphaeropedunculate to pyriform, walls rarely with light brown intracellular pigment, few thin and hyaline in KOH, lacking apparent Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 35 intracellular pigment, cells tightly adhering to obtuse apices to broadly lageniform to utriform one another in crush mounts. Pileus trama having pedicels and short necks with broad, hyaline, septate. Stipitipellis a cutis of cylindrical obtuse apices to rarely sphaeropedunculate, hyphae, cells 3–18 μm wide, walls thin and readily collapsing, walls thin and hyaline in KOH, hyaline in KOH, septate, without apparent lacking visible intracellular contents, many contents. Clamp connections absent. Type covered with an apical cap of amorphous, material damaged by growth of an imperfect mucilaginous material. Cheilocystidia 20–64 × fungus and what appears to have been insect 11–33 μm, crowded, sphaeropedunculate to activity. pyriform to cylindrical-clavate to broadly lageniform or utriform with pedicels and short General description: Pileus 0.8–4 cm in necks possessing broad, obtuse apices, frequently diameter, convex to nearly plane, minutely collapsing, walls thin and hyaline in KOH, umbonate or not; surface dry, glabrous, rugulose, lacking apparent contents or rarely with light faintly granular under hand lens; buttons dark brown intracellular pigment, few to several with brown (dark reddish brown, R) and at margin in an apical cap of amorphous, mucilaginous older specimens, dark yellow-brown (7F6–7E6, material. Lamellar trama convergent, hyaline. M; near raw umber, R but darker) elsewhere to Subhymenium cellular, hyaline. Pileipellis a dark olive brown to yellowish olive; margin at cystoderm, cells 20–64 × 11–31 μm, globose to times slightly striate, decurved. Stipe 1.2–5.2 cm sphaeropedunculate to pyriform to cylindrical- × 2–5 mm, equal to tapered above; surface dry, clavate to lageniform to clavate and pedicellate or glabrous; pale yellow (massicot yellow, R; 3A3– apedicellate, walls thin and hyaline in KOH, A4, M) to (straw yellow, R) to lemon yellow with containing dark brown intracellular pigment, apex at times whiter; solid becoming hollow; cells tightly adhering to one another in crush basal tomentum white. Lamellae free becoming mounts. Pileus trama hyaline, septate. remote at maturity, close, pinkish brown (pinkish Stipitipellis a cutis of cylindrical hyphae, avellaneous, R); edges, concolorous, fimbriate elements 3–24 μm wide, walls thin and hyaline in when viewed with a hand lens. Lamellulae 1–2 KOH, septate, without visible contents. Clamp tiers. Context in pileus solid, yellowish white to connections absent. Oleiferous hyphae present. white becoming at times water soaked. Stipe Mi. context yellowish white. Odor mild to none. Taste mild. Habit and habitat: Solitary to scattered to gregarious on soil or rotten angiospermous wood. Basidiospores 5.7–7.9 × 5.3–7.9 μm, Q = 0.93– Rarely found on rotten gymnospermous wood 1.29 (Lm = 6.9 μm, Wm = 6.3 μm, Qm = 1.10), very (Homola 1969). few globose, subglobose to inequilateral to predominantly broadly ellipsoid to ovate in face Material examined: U.S.A., ARIZONA: and profile views, circular in end views, apiculate, Cochise Co., Coronado National Forest, Tubb smooth, walls slightly thickened, subhyaline to Spring, Chiricahua Mountains, on aspen, pale yellow in KOH, contents not visible or of one 29.VII.1980, coll. HH Burdsall, Jr., HH Burdsall, to many scattered guttules sometimes giving Jr. 10978 (SFSU as Pluteus admirabilis). grainy appearances. Basidia 14–29 × 6–10 μm, CALIFORNIA: Marin Co., Audubon Canyon clavate, tetrasterigmate, walls thin and hyaline in Ranch, Pitcher Canyon, scattered on rotten wood KOH, contents granular to agranular. in mixed evergreen forest, 21.I.1980, C Calhoun, Pleurocystidia 28–69 × 11–33 μm, infrequent to C Calhoun 80-1472 (SFSU as Pluteus lutescens); common in abundance, scattered, predominantly Bolinas, scattered on dead hardwood log, cylindrical-clavate with pedicels and broad, 18.X.1981, coll. DE Desjardin, DE Desjardin 521 36 Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107

(SFSU as Pluteus lutescens); Muir Woods Puxico, Mingo National Wildlife Refuge, solitary National Mon., solitary under old California on decorticated hardwood, 23.IX.2006, coll. AS laurel log, 13.XII.1966, coll. DE Madden, DE Methven, Minnis 6-9-23-3 (SIU). NEW YORK: Madden 743 (SFSU as Pluteus nanus var. West Park, on rotten stump, 30.VII.1903, coll. FS lutescens). San Mateo Co., on wood, 10.I.1987, Earle, FS Earle 1589 (holotype of Pluteus coll. San Francisco Mycological Society Member, melleipes, NY); on rotten wood, 03.VIII.1903, WJ Sundberg I-10-87-4 (SIU). Sonoma Co., coll. FS Earle, FS Earle 1629 (NY as Pluteus Pepperwood Ranch Natural Preserve, Franz melleipes). OREGON: Glen Brook, dense fir Valley Road, scattered in soil among debris under forest of mostly second growth with few old oak Pseudotsuga menziesii, 16.XII.1994, coll. DE trees at 400-1,000 ft (122–305 m) elevation, Desjardin, DE Desjardin 6134 (SFSU as Pluteus 07.XI.1911, coll. WA Murrill, WA Murrill 760 lutescens). COLORADO: Pitkin Co., Snowmass (holotype of Pluteus fulvibadius, NY). Creek, on aspen, 11.VII.1976, coll. AH Smith, AH WAHINGTON: Clallam Co., Joyce, on Alnus, Smith 86834 (MICH as Pluteus lutescens var. 09.VI.1939, coll. AH Smith, AH Smith 14197 lutescens). ILLINOIS: Cook Co., Bemis Woods, (MICH as Pluteus lutescens var. americanus). 04.IX.2004, coll. IMA member, Sundberg 2004- WYOMING: Teton Co., Bridges Teton National IX-04-4 (SIU); Deer Grove Preserve, solitary, Forest, Turpin meadow, on wood, 04.VIII.1999, 9.IX.2006, coll. L Shernoff, Minnis 6-09-09-1 coll. MT Seidl, MTS 4677 (WTU as Pluteus (SIU); Seheller Woods, solitary on decorticated romellii). hardwood, 05.IX.2004, coll. IMA Foray participant, Sundberg 2004-IX-5-5 (SIU). Known distribution: Pluteus fulvibadius Shelby Co., near Shelbyville, Hidden Springs appears to be widely distributed throughout the State Forest, solitary on wood, 23.IX.2006, coll. U.S.A. and is often reported as Pluteus lutescens AM Minnis, Minnis 6-09-23-3 (SIU). Union Co., (Fr.) Bres., Pluteus nanus var. lutescens (Fr.) P. Trail of Tears State Park, solitary on hardwood, Karst., and Pluteus romellii (Britzelm.) Lapl. 01.XI.2003, coll. G Mueller, Minnis 3-11-01-2 Pluteus fulvibadius is not uncommon. Pluteus (SIU). INDIANA: McCormick’s Creek State Park, romellii has also been reported from Mexico on wood, 15.VIII.1981, coll. R Halling, N Smith- (Rodríguez and Guzmán-Dávalos 1999, 2001). Weber 4589 (MICH as Pluteus romellii). This Mexican material may be synonymous with MICHIGAN: Cheboygan Co., Hermit’s Bog, on P. fulvibadius as we understand it. moss and wet leaves, 08.VII.1965, coll. RL Homola, RL Homola 1360 (MICH as Pluteus Notes: The macromorphological descriptions of lutescens var. lutescens). Emmet Co., Sturgeon the holotypes of Pluteus fulvibadius and Pluteus Bay Area, in mud among deciduous leaves, melleipes were tailored from the protologues 19.VII.1965, coll. RL Homola, RL Homola 1402 (Murrill 1917). (MICH as Pluteus lutescens var. lutescens). Washtenaw Co., Ann Arbor, 1766 Glenwood Rd., Singer (1956), Smith and Stuntz (1958), and on deciduous twig, 16.VI.1964, coll. RL Homola, Banerjee and Sundberg (1993a) all examined the RL Homola 813 (MICH as Pluteus lutescens var. types of P. fulvibadius and P. melleipes. Singer lutescens); at home of Dr. AH Smith, on wet soil, (1956) and Smith and Stuntz (1958) noted that P. 10.VI.1965, coll. AH Smith, RL Homola 1284 melleipes lacked obvious intracellular pigment in (MICH as Pluteus lutescens var. lutescens). the pileipellis. We believe this observation is due Pellston Hills west of Pellston, gregarious on to the poor condition of the type collection and decayed hardwood log, 09.VII.1956, coll. HD should not be emphasized. Banerjee and Thiers, HD Thiers 3045 (SFSU as Pluteus nanus Sundberg (1993a) erroneously observed angular var. lutescens). MISSOURI: Wayne Co., near basidiospores in the type collection of P. Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 37 fulvibadius and suggested that it was a member number of broadly fusoid-ventricose or close relative of the Entolomataceae Kotl. & pleurocystidia, a larger basidiocarp size, and a Pouzar. Homola (1969) classified P. fulvibadius more yellowish brown pileus in a more or less in subsection Mixtini presumably based on his Western U.S.A. P. lutescens var. americanus. interpretation of data presented by Smith and The more or less Eastern U.S.A. P. lutescens var. Stuntz (1958). We do not agree with this lutescens tended to have fewer broadly fusoid- interpretation since the pileipellis in this species ventricose pleurocystidia, a smaller basidiocarp is predominantly made up of a cystoderm of size, and more olive tones in the pileus. We were globose, sphaeropedunculate, and pyriform unable to examine fresh material correlating with elements. However, there are at times a few the two varieties, and our examination of elements that are more cylindrical-clavate to pleurocystidia from dried collections from both of clavate in the pileipellis. We do not feel that the varieties did not reveal consistent differences these are cystidioid elements like those found in between the two. Therefore, we have not members of subsection Mixtini. The observation recognized varieties. Future study may reveal of cuticular cells that tightly adhere to one that the two taxa are distinct species or varieties. another supports this assessment. These cells do In this case, P. fulvibadius may be used for the not strongly adhere to one another in species western taxon and P. melleipes may be used for classified in subsection Mixtini. the more eastern taxon.

Homola (1969) discussed two taxa, Pluteus Several similar species discussed under P. lutescens (Fr.) Bres. var. lutescens and the romellii differ from the American P. fulvibadius. provisional Pluteus lutescens var. americanus Homola in his dissertation. Subsequently, (11) Pluteus homolae Minnis & Sundb., nom. Homola (1972) did not formally recognize the nov. Fig. 27. provisional variety and presented it as Pluteus Mycobank: 512855 lutescens var. sp. Homola (1969, 1972) ≡ Prunulus ludovicianus Murrill, North mentioned differences in the shape of the American Flora 9: 330. 1916. Type citation: pleurocystidia between American and European “Type collected on the ground in a wet thicket at isolates of P. lutescens. We agree with his New Orleans, Louisiana, September 8, 1908, F. S. observations as we found many pleurocystidia Earle 132 (herb. N. Y. Bot. Gard.)”. with broader, elongate clavate shapes in the ≡ Mycena ludoviciana (Murrill) Murrill, European collections that were examined. Based Mycologia 8: 220. 1916. on these observations, we recognize the European collections, correctly named Pluteus Etymology: Named in honor of Richard Louis romellii (Britzelm.) Lapl., as distinct from the Homola for his contributions to the study of American collections. Additionally, examination Pluteus and to amateur mycological associations of type material revealed that Pluteus fulvibadius in North America. and Pluteus melleipes are identical with other examined American collections. We have Diagnostic characters: Pileus brownish; selected P. fulvibadius as the correct name for lamellar edges fuscous; pileipellis lacking this species as it has equal priority with P. cystidioid elements. melleipes according to the International Rules of Botanical Nomenclature (McNeill et al. 2006). Description of the type specimens: Prunulus ludovicianus (holotype) With regards to the use of two varieties by Pileus 3 cm in diameter, convex becoming Homola (1969, 1972), he recognized a larger expanded, gibbous; surface moist, glabrous; dark 38 Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 tan or nearly fuscous; margin scarcely striate; Habit and habitat: Solitary on soil in a wet fleshy, firm. Stipe 5 cm x 5 mm; surface glabrous, thicket. shining; pallid; solid. Lamellae free or nearly so, medium breadth, crowded, whitish. Material examined: U.S.A., LOUISIANA: New Orleans, on the ground in a wet thicket, 08.IX.1908, coll. FS Earle, FS Earle 132 Examination of the dried basidiocarp revealed or (holotype of Prunulus ludovicianus, NY). clarified some characters not mentioned in the above macromorphological description based on Known distribution: This species is only notes on fresh material. Pileal margin striate known from the type collection. It is reported approximately 1/3 to disc, slightly incurved. from Louisiana, U.S.A. (Murrill 1916). Stipe basal tomentum pallid, abundant. Lamellae free. Lamellar edges with fuscous coloration. Notes: The macromorphological description of the holotype when fresh was adapted from the Basidiospores 5.3–7.0 × 4.8–6.6 μm, Q = 1.00– protologue (Murrill 1916). Based on our study of 1.36 (Lm = 6.4 μm, Wm = 5.7 μm, Qm = 1.12), the dried holotype, we have supplemented this globose to subglobose to mostly broadly ellipsoid description with more data. to ellipsoid to slightly ovate in face and profile views, circular in end views, apiculate, smooth, This species is clearly a Pluteus. Since the epithet walls slightly thickened, subhyaline to pale yellow ‘ludovicianus’ is already in use in Pluteus (see in KOH, contents not visible or of scattered drops Pluteus ludovicianus Murrill), a new name was giving grainy appearances. Basidia 22–34 × 7–11 given. μm, clavate, tetrasterigmate, walls thin and hyaline in KOH, occasionally with granular Pluteus luctuosus Boud. is a similar species found contents. Pleurocystidia 44–66 × 22–35 μm, in Europe. According to the description of P. abundant, broadly lageniform to utriform with luctuosus presented by Vellinga (1990), P. pedicels and with necks usually having relatively homolae appears to differ in having fewer of the broad, obtuse apices, often collapsing, walls thin lageniform shaped pleurocystidia with long and hyaline in KOH, no apparent contents. necks. The Asian Pluteus fusconigricans (Berk. & Cheilocystidia 28–56 × 11–24 μm, crowded, Broome) Sacc. has pigmented pleurocystidia clavate to pyriform to lageniform, walls thin and (Pegler 1986) which distinguish it from P. hyaline in KOH, with few exceptions filled with homolae. Pluteus submarginatus E. Horak, a brown intracellular pigment. Lamellar trama South American taxon (Horak 1964), is convergent, hyaline. Subhymenium cellular, distinguished by its more lageniform hyaline. Pileipellis a cystoderm, cells 26–64 × pleurocystidia with long necks and occurrence on 18–31 μm, mostly globose to sphaeropedunculate decaying wood of Nothofagus. Three South to more or less pyriform to clavate,walls thin and American taxa classified in stirps Luctuosus, hyaline in KOH, containing brown intracellular Pluteus beniensis Singer, Pluteus riograndensis pigment. Context in pileus composed of 3–18 μm Singer, and Pluteus rimosoaffinis Singer (Singer wide hyphae, walls thin and hyaline in KOH, 1958) are also similar in appearance and differ in septate, no apparent contents. Stipitipellis a cutis part by having darkly colored lamellar edges that of cylindrical hyphae, 4–17 μm wide, walls thin are far less prominent in pigmentation darkness and hyaline in KOH, septate, usually with no and uniformity. We are not aware of any other apparent contents but some hyphae filled with species with the combination of this type of brown intracellular pigment. Clamp connections cuticle and distinctly darkly colored lamellar absent. Mi. edges. Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 39

(12) Pluteus jamaicensis Murrill, Mycologia Description of the type specimens: 3: 278. 1911. Type citation: “Type collected on Pluteus jamaicensis (holotype) rotten wood at Castleton Gardens, Jamaica, October 28, 1902, F. S. Earle 220.” Figs. 28– Pileus 1–3 cm in diameter, expanded, obtuse; 29. surface rugose, crustose-areolate, not striate; ≡ Pluteus aethalus var. jamaicensis dark brown, paler with age, thin. Stipe 2 cm x 2 (Murrill) Dennis, Bull. Soc. Mycol. France 69: mm, enlarged above and below; surface glabrous, 153. 1953. base white-tomentose; solid. Lamellae free, = Pluteus alachuanus Murrill, Proc. Florida broad, subcrowded, ventricose, white becoming Acad. Sci. 7: 118. 1944 (1945). Type citation: pink. “Type collected by W. A. Murrill on a rotten sweet-gum log in a low hammock at Magnesia The holotype was not examined for Springs, Fla., Feb. 11, 1939 (F 18713).” micromorphological characters. See Singer = Pluteus venosus Singer, Lloydia 21: 269. 1958 (1956), Smith and Stuntz (1958), and Banerjee (1959). Type citation: “Ad lignum foliaque and Sundberg (1993a) for descriptions of such emortua, Matheson Hammock, Dade Co., characters from the type collection. Floridae, Singer F 1107 (F), typus.” ≡ Pluteus psichriophorus var. venosus Pluteus alachuanus (microscopic description is Singer, Trans. Brit. Mycol. Soc. 39: 215. 1956. ad based on isotype material) int. (as Pluteus psychriophorus var. venosus Singer). This is a nom. inval. Pileus 3–3.5 cm in diameter, convex to plane, not umbonate; surface glabrous, hygrophanous, disc Diagnostic characters: Pileus brown; stipe with serpentine reticulate fuliginous lines; pale white. Microscopically, pleurocystidia usually umbrinous, disc fuliginous; margin straight, frequent; utriform without long, narrow necks to even, entire, fertile. Stipe 5 cm x 0.3–0.4 cm, more or less cylindrical; basidiospores tapering upwards; surface glabrous above predominantly globose to subglobose; pileipellis becoming tomentose below, shining, striate; lacking cystidioid elements; distribution tropical whitish. Lamellae free, broad, close, ventricose, to subtropical in North America. inserted, pallid becoming pink; edges entire. Context very thin, white. Taste mild. Odor none. Selected descriptions and illustrations: Singer, Trans. Brit. Mycol. Soc. 39: 201-202. Basidiospores 5.7–7.0 × 5.7–7.0 μm, Q = 0.93– 1956; Singer, Lloydia 21: 293. 1958; Pegler, 1.15 (Lm = 6.2 μm, Wm = 6.0 μm, Qm = 1.03), Agaric Flora of the Lesser Antilles, 323-324, Icon. predominantly globose to subglobose to few 326, Figs. A-E. 1983; Banerjee and Sundberg, broadly ellipsoid to ovate in face and profile Mycotaxon 49: 422, Icon. 422-423, Fig. 16. 1993a views, circular in end views, apiculate, smooth, (as Pluteus jamaicensis). walls slightly thickened, subhyaline to pale yellow in KOH, contents not visible or of one to many Dennis, Bull. Soc. Mycol. France 69., 153-154, scattered guttules. Basidia 11–18 × 7–9 μm, Icon. legend 197-198, Plate II. 1953 (as Pluteus squat-cylindrical to clavate, tetrasterigmate, walls aethalus var. jamaicensis). thin and hyaline in KOH, contents granular to lacking. Pleurocystidia 28–51 × 13–23 μm, Singer, Trans. Brit. Mycol. Soc. 39: 195. 1956; common in abundance, pyriform to ellipsoid to Banerjee and Sundberg, Mycotaxon 49: 415-416, utriform to more or less cylindrical with pedicels Icon. 416-417, Fig. 2. 1993a (as Pluteus and broad, obtuse apices, often collapsing, walls alachuanus). thin and hyaline in KOH, without visible 40 Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 intracellular contents, some covered with an hyaline. Pileipellis a cystoderm, cells 25–66 × apical cap of amorphous, mucilaginous material. 20–33 μm, globose to sphaeropedunculate to Cheilocystidia 19–39 × 9–17 μm, crowded, somewhat pyriform, walls thin and hyaline in sphaeropedunculate to pyriform to somewhat KOH, containing brown intracellular pigment, utriform and pedicellate, walls thin and hyaline cells moderately adhering to one another in crush in KOH, lacking apparent contents, some with an mounts. Pileus trama hyaline, septate. apical cap of amorphous, mucilaginous material. Stipitipellis a cutis of cylindrical hyphae, 3–19 Lamellar trama hyaline. Subhymenium cellular. μm wide, walls thin and hyaline in KOH, septate, Pileipellis a cystoderm, cells 22–48 × 17–34 μm, without apparent contents to some caulocystidia- globose to sphaeropedunculate, walls thin and like elements with brown intracellular pigment. hyaline in KOH, containing brown intracellular Clamp connections absent. pigment, cells moderately adhering to one another in crush mounts. Pileus trama hyaline, The pileus surface possesses contaminant fungus septate. Stipitipellis a cutis of cylindrical hyphae, growth. 2–23 μm wide, walls thin and hyaline in KOH, septate, without apparent contents. Clamp Habit and habitat: Solitary to gregarious to connections absent. subcespitose on rotten, angiospermous wood or leaves. Pluteus venosus (holotype) Material examined: JAMAICA: Castleton Pileus 1.5 cm in diameter; surface glabrous, Gardens, subcespitose on rotten wood, venose; (snuff brown to cinnamon brown, R); 28.X.1902, coll. FS Earle, FS Earle 220 (holotype margin transparently striate on edge, dries of Pluteus jamaicensis, NY). U.S.A., FLORIDA: smooth. Stipe 3 cm x 1.5 mm; hyaline. Lamellae Alachua Co., seven miles (11 km) west of free, broad, ventricose, pink. Odor none. Gainesville, gregarious to subcespitose on rotten wood (probably Quercus virginiana), Basidiospores 5.3–7.5 × 5.3–7.0 μm, Q = 1.00– 06.VIII.1965, coll. BF Isaacs, BF Isaacs 2460 1.15 (Lm = 6.6 μm, Wm = 6.3 μm, Qm = 1.04), (MICH as Pluteus eliae). Dade Co., Miami, predominantly globose to subglobose to few Matheson Hammock, on wood or leaves, broadly ellipsoid to inequilateral in face and 17.X.1942, coll. R Singer, Singer F 1107 (holotype profile views, circular in end views, apiculate, of Pluteus venosus, F as Pluteus dennisii). smooth, walls slightly thickened, subhyaline to Magnesia Springs, gregarious on a rotten sweet- pale yellow in KOH, contents not visible or of one gum (Liquidambar styraciflua) log in a low to many scattered guttules. Basidia 18–25 × 7–9 hammock, 11.II.1939, coll. WA Murrill, Murrill F μm, clavate, tetrasterigmate,walls thin and 18713 (isotype of Pluteus alachuanus, NY). hyaline in KOH, contents rarely granular to usually lacking. Pleurocystidia 40–61 × 14–24 Known distribution: In the U.S.A., Pluteus μm, scattered, common in abundance, more or jamaicensis is known from Florida (Singer 1956, less cylindrical with pedicels and broad, obtuse 1958; Homola 1969, 1972 (as Pluteus eliae)). apices, collapsing easily, walls thin and hyaline in Pluteus jamaicensis is also known from KOH, without visible intracellular contents. Venezuela (Dennis 1970) and Argentina (Singer Cheilocystidia 31–50 × 13–31 μm, crowded, 1958) in South America and has been reported clavate to pyriform to somewhat utriform and from the Caribbean (Murrill 1911, Pegler 1983). pedicellate, collapsing easily, walls thin and hyaline in KOH, without visible contents. Notes: The macromorphological description of Lamellar trama hyaline. Subhymenium cellular, the holotype of Pluteus jamaicensis was modified Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 41 from the protologue (Murrill 1911). The Homola (1969, 1972) overemphasized the globose macromorphological description of the holotype nature of the basidiospores in the collection he of Pluteus alachuanus located at the Florida identified as Pluteus eliae. We observed that this Museum of Natural History (FLAS) was also collection has basidiospores that are more or less adapted from the protologue (Murrill 1944). The subglobose, and the collection should have been macromorphological description of the holotype identified as P. jamaicensis. of Pluteus venosus was tailored from Singer’s (1956) provisional description and Singer’s Pluteus fluminensis Singer, a member of stirps unpublished notes (F). The holotype collection of Jamaicensis (Singer 1986), is nearly identical Pluteus venosus has not had its label updated and differs according to Singer (1958) in having from a prior name used by Singer. Data from a condensed pigment bodies in the pileipellis single collection identified by Homola (1969, elements. Smith and Stuntz (1958) believe this 1972) as Pluteus eliae Singer was not included character to be an artifact and not valid above under a general description heading since taxonomically. We tend to agree, but more work the specimen was not type material and nothing needs to be done in this area. Pluteus could be added to the Homola (1969, 1972) dominicanus Singer (stirps Jamaicensis Singer description. 1986) differs in having larger basidiospores and a lighter colored pileus (Singer 1961). Pluteus Singer (1956) considered Pluteus alachuanus to paraensis Singer, also a member of stirps be a synonym of Pluteus jamaicensis. Neither Jamaicensis (Singer 1986), is distinguished from Smith and Stuntz (1958) nor Homola (1969, P. jamaicensis in that it has a fuscous-fibrillose 1972) studied P. alachuanus. Banerjee and stipe (Singer unpublished notes, F). Pluteus Sundberg (1993a) considered the two species to praerugosus Murrill has a more temperate be distinct. Based on our observations and data distribution in North America than P. presented in other studies, we agree with Singer’s jamaicensis (see discussion under Pluteus opinion that P. jamaicensis and P. alachuanus praerugosus). Finally, Pluteus pulverulentus are synonyms. Murrill and the species grouping around stirps Pulverulentus are distinguished by their almost Pluteus venosus was described by Singer as a geometrically globose basidiospores (Singer 1958, species belonging to subsection Mixtini. We were 1986). unable to observe any of the cystidioid elements in the pileipellis that Singer (1956, 1958) saw in the type collection. Because of this, P. venosus is (13) Pluteus ludovicianus Murrill, North correctly classified in section Celluloderma. It is American Flora 10: 133. 1917. Type citation: our opinion that P. venosus is a synonym of P. “Type collected in soil in a wet thicket at jamaicensis. However, we did observe some Chalmette, New Orleans, Louisiana, September hyphae in the stipe of the type collection of P. 8, 1908, F. S. Earle 130 (herb. N. Y. Bot. Gard.).” venosus that have brown intracellular pigment, Fig. 30. something not seen in the other specimens examined. Because of the limited amount of material that was available for study, we have Diagnostic characters: Macroscopically, chosen not to emphasize this difference at a pileus hygrophanous changing from a dark tan to taxonomic level. According to Vellinga (1990), pale fuliginous; striate; stipe pallid to pale- Pluteus cervinus (Schaeff.) P. Kumm. is another brown. Microscopically, pleurocystidia broadly species that may or may not have brown lageniform to utriform to cylindrical; pileipellis intracellular pigment in the stipitipellis. lacking cystidioid elements. 42 Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107

Selected descriptions and illustrations: to pyriform and usually pedicellate with a single Smith and Stuntz, Lloydia 21: 127-128. 1958; occasional short mucro, walls thin and hyaline in Banerjee and Sundberg, Mycotaxon 49: 424, KOH, filled with brown intracellular pigment, Icon. 424-425, Fig. 20. 1993a. cells moderately adhering to one another in crush mounts. Pileus trama hyaline, septate. Description of the type specimens: Stipitipellis a cutis of cylindrical hyphae, 2–25 Pluteus ludovicianus (holotype) μm wide, walls thin and hyaline in KOH, septate, without apparent contents. Clamp connections Pileus 5 cm in diameter, convex becoming absent. expanded, slightly plicate; surface hygrophanous, glabrous; dark tan, pale fuliginous dried; margin Habit and habitat: Solitary on soil in wet striate, paler; firm. Stipe 7 cm x 5–8 mm, thickets. tapered upwards; surface smooth, glabrous, shining; pallid or pale brownish; hollow; base Material examined: U.S.A., LOUISIANA: New subbulbous. Lamellae free, broad, crowded, Orleans, Chalmette, in soil in a wet thicket, white becoming salmon colored; edges entire and 08.IX.1908, coll. FS Earle, FS Earle 130 concolorous. (holotype of Pluteus ludovicianus, NY).

Basidiospores 6.2–7.5 × 5.3–7.0 μm, Q = 0.93– Known distribution: This species is only 1.33 (Lm = 6.8 μm, Wm = 5.9 μm, Qm = 1.16), known from the type collection. It is reported globose, subglobose, broadly ellipsoid, ellipsoid from Louisiana, U.S.A. (Murrill 1917). It may to ovate in face and profile views, circular in end also be more widespread in the southern part of views, apiculate, smooth, walls slightly thickened, the U.S.A. and may have been reported from subhyaline to pale yellow in KOH, contents not Mexico as Pluteus pallescens P.D. Orton (see visible or of scattered guttules giving grainy discussion). appearances. Basidia 18–29 × 7–12 μm, clavate, tetrasterigmate, walls thin and hyaline in KOH, Notes: The macromorphological description of with granular contents or lacking visible the holotype was tailored from the protologue contents. Pleurocystidia 44–69 × 13–31 μm, (Murrill 1917). Smith and Stuntz (1958) and infrequent to common in abundance, more or Banerjee and Sundberg (1993a) emphasized a less cylindrical to broadly lageniform to utriform somewhat plicate-striate margin in the dried with pedicels and short necks having broad, material. Based on our observations, this fungus obtuse apices, collapsing easily, walls thin and is striate, but it is not distinctly plicate-striate as hyaline in KOH, lacking visible intracellular there does not appear to be folded pleats between contents to rarely filled with very light brown the striations. intracellular pigment, at times covered by apical caps of amorphous, mucilaginous material with Pluteus phlebophorus (Ditmar : Fr.) P. Kumm. basidiospores usually adhering. Cheilocystidia differs in its pileus coloration and possession of 26–44 × 17–28 μm, crowded, often similarly narrower, lageniform lamellar cystidia. Pluteus shaped to pleurocystidia with cylindrical to griseoluridus P.D. Orton, a European species, cylindrical-clavate to subglobose shapes, has a similar coloration, but it also differs in its collapsing easily, walls thin and hyaline in KOH, narrow form of lamellar cystidia. The European lacking apparent contents to rarely filled with Pluteus satur Kühner & Romagn., considered a very light brown intracellular pigment. Lamellar synonym of Pluteus pallescens P.D. Orton by trama hyaline. Pileipellis a cystoderm, cells 21– Orton (1986) but not so by Vellinga (1990), 52 × 12–40 μm, globose to sphaeropedunculate appears to be quite similar to Pluteus Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 43 ludovicianus and may be conspecific. If so, P. enlargement at base; dingy honey pallid to watery ludovicianus has priority. Pluteus pallescens has pallid and slightly silvery streaked to watery been reported from Mexico (Rodríguez and brownish at base; fragile. Lamellae free, broad, Guzmán-Dávalos 1999, 2001) and these close, white to pallid white becoming pinkish to collections also may be the same as P. grayish vinaceous. Lamellulae irregular, ludovicianus indicating a subtropical to tropical abundant. Context soft, pallid, lacking color distribution in North America. Critical change after handling. Odor none to slight. comparisons using a variety of techniques are Taste disagreeable to nauseous. needed for both the European and American specimens in order to gain a better Examination of the dried basidiomata revealed understanding of these fungi. hollow stipes.

Basidiospores 5.3–7.5 × 4.4–6.6 μm, Q = 1.00– (14) Pluteus pallidus Homola, Mycologia 64: 1.36 (Lm = 6.3 μm, Wm = 5.3 μm, Qm = 1.19), 1232. 1972 (1973). Type citation: “Specimen globose, subglobose, broadly ellipsoid, ellipsoid typicum in Herb. Univ. Mich. Conservatum; to ovate in face and profile views, circular in end lectum prope Tahquamenon Falls State Park, views, apiculate, smooth, walls slightly thickened, Michigan, 17 Aug., 1963, Homola 522.” Fig. 31. subhyaline to pale yellow in KOH, contents of a single large oil drop inside or scattered smaller Diagnostic characters: Macroscopically, drops giving grainy appearances. Basidia 23–39 pileus whitish; stipe white. Microscopically, × 6–10 μm, clavate, tetrasterigmate, walls thin pleurocystidia lageniform often with long, narrow and hyaline in KOH, often with granular necks; pileipellis lacking cystidioid elements. contents. Pleurocystidia 41–66 × 17–29 μm, abundant, more or less clavate to lageniform Selected descriptions and illustrations: having pedicels and long necks with obtuse Homola, A Systematic Study of the Section apices, often collapsing, walls thin and hyaline in Celluloderma Fayod of the Genus Pluteus Fries in KOH, no apparent contents. Cheilocystidia 34– North America, 99-104, Icon. 100-101, Pl. IX, 55 × 7–23 μm, plentiful, versiform with clavate to Figs. 1-5. 1969; Homola, Mycologia 64: 1232- utriform to lageniform to cylindrical shapes, 1234, Icon. 1233, Fig. 13. 1972. walls thin and hyaline in KOH, lacking apparent contents. Lamellar trama convergent, hyaline. Description of the type specimens: Subhymenium cellular, hyaline. Pileipellis a Pluteus pallidus (macroscopic description is cystoderm, cells 20–44 × 11–34 μm, mostly composite of data from holotype and two globose to sphaeropedunculate to pyriform, paratypes, microscopic description is composite tightly adhering to each other in squash mounts, of data from the two paratypes) walls slightly thickened and hyaline in KOH, no apparent contents. Hyphal cells immediately Pileus 2.4–4 cm in diameter, convex to broadly below and connecting to the one cell thick convex becoming plane or depressed; surface cystoderm layer somewhat inflated but not glabrous, hygrophanous, disc rugose to reticulate appearing to be part of the pileipellis. Pileus sometimes becoming smooth; margin striatulate trama hyaline, septate. Stipitipellis a cutis of to translucent-striate, sometimes lobed; pale buff cylindrical hyphae, 3–33 μm wide, walls thin and (pale pinkish buff, R) to pinkish-grey hyaline in KOH, septate, no apparent contents. (avellaneous, R), pinker when young, fading Clamp connections absent. Oleiferous hyphae white to whitish in age starting at disc. Stipe 2– present. Mi. 4.1 cm x 1.2-4 mm, equal sometimes with slight 44 Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107

Habit and habitat: Gregarious on rotten, None of the species of Pluteus with whitish pilei dicotyledonous logs including Fagus (Singer’s from subsection Eucellulodermini discussed unpublished descriptions at F) and possibly above are sufficiently known. Numerous Fraxinus logs. additional collections are needed to clarify species boundaries and relationships. Additionally, P. pallidus may merely be a form of Material examined: U.S.A. MICHIGAN: Luce Pluteus phlebophorus (Ditmar : Fr.) P. Kumm. Co., Tahquamenon Falls State Park, gregarious that lacks abundant brown pigment in the on rotten hardwood log, 17.VIII.1963, coll. RL pileipellis elements. If this is found to be true, P. Homola, Homola 522 (holotype of Pluteus pallidus could be reduced to the varietal rank pallidus, MICH). Washtenaw Co., Sharon under P. phlebophorus or synonymized. Hollow, near Manchester, on hardwood, 16.VIII.1960, coll. RL Shaffer, Shaffer 2633 (15) Pluteus phaeocyanopus Minnis & (paratype of Pluteus pallidus, MICH); on a Sundb., sp. nov. Fig. 32. Fraxinus (?) log, 02.VII.1960, coll. AH Smith, MycoBank: 512857 Smith 62487 (paratype of Pluteus pallidus, MICH). Etymology: The term ‘phaeo’ in the epithet refers to the pigmented lamellar cystidia of a Known distribution: Pluteus pallidus is species that otherwise resembles Pluteus known from Michigan, U.S.A. (Homola 1969, cyanopus in many regards. 1972) and Czechoslovakia (Singer 1977). Latin diagnosis: A Pluteo cyanopo differt Notes: The macromorphological description of habens pleurocystidia forma dissimili et cystidia the type specimens was adapted from the pigmentifera. protologue (Homola 1972). Holotype: U.S.A., CALIFORNIA: San Mateo Of the Pluteus species with whitish colored pilei, Co., San Francisco Watershed, solitary on dead only a small number of species belonging to Quercus log, 16.XII.1966, coll. HD Thiers, HD subsection Eucellulodermini may be confused Thiers 18076 (SFSU). with P. pallidus. Pluteus roseocandidus G.F. Atk., a North American taxon, is distinguished Diagnostic characters: Pileus dark brown; from P. pallidus in usually having more broadly stipe whitish becoming grayish green similarly to shaped pleurocystidia than the narrow Pluteus salicinus toward the base. lageniform pleurocystidia with long, narrow Microscopically, pleurocystidia narrowly necks of P. pallidus. Another species from lageniform; lamellar cystidia brown pigmented; tropical South America, Pluteus hololeucus pileipellis lacking cystidioid elements. Singer, is distinguished by its sulcate pileus margin and more globose shaped basidiospores Description of the type specimens: (Singer 1977; Singer’s unpublished notes, F). Pluteus inquilinus Romagn., a European species Pileus 2–4 cm in diameter, plano-convex to often discussed under incorrect names including plane, may be subumbonate; surface smooth, disc Pluteus alborugosus Kühner & Romagn. and slightly rugulose, moist, somewhat granulose, Pluteus semibulbosus sensu J.E. Lange, is quite slightly hygrophanous; dark watery brown near similar. Based on the data presented by Vellinga chestnut brown to near snuff brown to Saccardo’s (1990), P. inquilinus differs from P. pallidus in umber to buckthorn brown (R), disc a hint darker having caulocystidia. and margin fading to near sayal brown; margin Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 45 entire, eroded with age, decurved. Stipe 2–5 cm μm wide, walls thin and hyaline in KOH, septate, × 4–8 mm, equal; surface dry, glabrous, innately usually lacking apparent contents to rarely with striate; whitish to appearing somewhat brown intracellular pigment. Clamp connections translucent and developing distinct grayish absent. Oleiferous hyphae present. Mi. greenish to grayish olive shades toward the base; stuffed to hollow. Lamellae free, broad, close to Habit and habitat: Solitary to gregarious on subdistant, ventricose, typically colored for a dead wood of Quercus. Pluteus, thin, somewhat fragile; edges entire concolorous. Lamellulae in several tiers. Context Material examined: U.S.A., CALIFORNIA: in pileus white. Stipe context concolorous, San Mateo Co., San Francisco Watershed, unchanging. Odor not distinctive. Taste not gregarious on dead Quercus logs, 04.XII.1964, distinctive. coll. HD Thiers, HD Thiers 11845 (MICH); San Francisco Watershed, solitary on dead Quercus Basidiospores 6.2–8.4 × 5.7–7.9 μm, Q = 1.00– log, 16.XII.1966, coll. HD Thiers, HD Thiers 1.21 (Lm = 7.3 μm, Wm = 6.8 μm, Qm = 1.09), few 18076 (holotype of Pluteus phaeocyanopus, globose, subglobose to broadly ellipsoid to SFSU). predominantly more or less ovate in face and profile views, circular in end views, apiculate, Known distribution: Pluteus phaeocyanopus smooth, walls somewhat thickened, subhyaline to is known thus far only from California, U.S.A. pale yellow in KOH, contents not visible or of one to numerous guttules. Basidia 15–32 × 8–10 μm, Notes: The type description is a composite of clavate, tetrasterigmate, walls thin and hyaline in data from all of the examined collections. KOH, with granular contents or lacking visible contents. Pleurocystidia 50–86 × 11–29 μm, Pluteus phaeocyanopus was found in material scattered, common, lageniform having pedicels borrowed from the herbarium at San Francisco and long necks with narrow, obtuse State University (SFSU) that was originally apices, walls thin and hyaline in KOH, often with identified as Pluteus cyanopus Quél. No one brown intracellular pigment to without visible other than Harry Thiers took notes on fresh contents, sometimes with apical cap of material, but Walter Sundberg was present when amorphous, mucilaginous material. the holotype was collected. The Cheilocystidia 28–68 × 7–22 μm, crowded, macromorphological description is based on subglobose to pyriform to lageniform with short Thiers’ notes. Microscopic examination revealed necks having narrow, obtuse apices to narrowly distinctive characters and a new taxon is cylindrical, walls thin and hyaline in KOH, often warranted. containing brown intracellular pigment to without apparent contents, sometimes with Some Pluteus species stain greenish blue to apical cap of amorphous, mucilaginous material. bluish to bluish gray on the stipe upon bruising Lamellar trama convergent, hyaline. (see discussion of Pluteus cyanopus). Of these, Subhymenium cellular, hyaline. Pileipellis a only P. cyanopus, which is classified in cystoderm, cells 22–59 × 12–34 μm, subsection Eucellulodermini, may be confused sphaeropedunculate to globose to pyriform and with P. phaeocyanopus. The two species are with or without pedicels, walls thin and hyaline in distinguished by pleurocystidial shape and the KOH, usually possessing brown intracellular presence of pigment in the lamellar cystidia. pigment, cells tightly adhering to each other in Pluteus phaeocyanopus has more narrowly crush mounts. Pileus trama hyaline, septate. lageniform shaped pleurocystidia than the Stipitipellis a cutis of cylindrical hyphae, 3–24 broadly lageniform to utriform shaped 46 Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 pleurocystidia of P. cyanopus. Pluteus Kränzlin, Fungi of Switzerland, Vol. 4, 126, Icon. phaeocyanopus also has lamellar cystidia 126-127, photograph and Figs. A-D. 1995 (as containing brown intracellular pigment, a feature Pluteus phlebophorus). not found in P. cyanopus. Homola, A Systematic Study of the Section (16) Pluteus phlebophorus (Ditmar : Fr.) P. Celluloderma Fayod of the Genus Pluteus Fries in Kumm., Der Führer in die Pilzkunde, 98. 1871. North America, 70-76, Icon. 71-72, Pl. V, Figs. 1- Figs. 33–35. 5. 1969; Homola, Mycologia 64: 1222-1225, Icon. ≡ Agaricus phlebophorus Ditmar : Fr., in 1212 and 1223, Figs. 2,4,5, and 7 and 11. 1972 (as Sturm, Deutschlands Flora 3: 31. 1817 Pluteus chrysophaeus). (basionym). Type citation: none seen. Sanctioned in Systema Mycologicum 1, 200. 1821 Description of the type specimens: with collection citation: “Uterque in ligno putrido Pluteus admirabilis var. fuscus (designated Fagi, passim. Jul.–Oct.” lectotype) ≡ Pluteus nanus subsp. phlebophorus (Ditmar : Fr.) Konrad & Maubl., Icones Selectae Basidiocarps 1–2' (2.5–5 cm) high. Pileus 6–10 Fungorum 1: pl. 23. 1924. lines (1.3–2.1 cm) in diameter; brown or = Pluteus admirabilis var. fuscus Peck, Rep. yellowish brown. Stipe 0.5–1 lines (1.1–2.1 mm) (Annual) New York State Mus. Nat. Hist. 38: 138. thick. 1885. Type citation: “Decaying wood and prostate trunks in forests. Common in hilly and From the dried herbarium material: Pileus plane, mountainous districts. July to September.” slight umbo present or absent; surface glabrous with or without a slightly rugulose to reticulate Types and typifications: There is no type disc; brown with a darker colored disc; margin specimen for Pluteus phlebophorus (see decurved. Stipe equal to slightly enlarged discussion). towards the base; innately striate; glabrous; pale colored; hollow. Lamellae free, broad, ventricose, Type (Pluteus admirabilis var. fuscus): U.S.A., close; edges entire. Some minor insect damage is New York: St. Lawrence Co., Star Lake, 12.VIII., present. coll. CH Peck, CH Peck, s.n. (NYS)—Lectotype designated here. Basidiospores 6.1–7.9 × 4.9–6.7 μm, Q = 1.00– 1.33 (Lm = 7.0 μm, Wm = 6.1 μm, Qm = 1.15), few Diagnostic characters: Pileus brown colored; globose to subglobose to predominantly ovate, stipe whitish and occasionally becoming broadly ellipsoid to ellipsoid to rarely yellowish to tan at the base. Microscopically, inequilateral in face and profile views, circular in basidiospores not predominantly globose to end views, apiculate, smooth, walls slightly subglobose; pleurocystidia narrowly lageniform thickened, subhyaline to pale yellow in KOH, often with long, narrow necks; pileipellis lacking contents not visible or of one to many scattered cystidioid elements. guttules. Basidia 17–36 × 8–11 μm, clavate, tetrasterigmate, walls thin and hyaline in KOH, Selected descriptions and illustrations: contents granular to agranular. Pleurocystidia Orton, British Fungus Flora: Agarics and Boleti, 47–81 × 14–27 μm, scattered, common in Vol. 4, Pluteaceae: Pluteus and Volvariella, 45- abundance, rarely pyriform to typically narrowly 47, Icon. 94-95, Fig. 52. 1986; Vellinga, Pluteus, to broadly lageniform with pedicels and short to In: Bas et al., Flora Agaracina Neerlandica, Vol. quite long necks having obtuse apices to 2, 51, Icon. 50, Fig. 31. 1990; Breitenbach and infrequently lacking necks, walls thin and hyaline Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 47 in KOH, lacking apparent intracellular contents. 1.36 (Lm = 6.4 μm, Wm = 5.5 μm, Qm = 1.18), Cheilocystidia 34–70 × 12–31 μm, crowded, globose, subglobose, ovate, broadly ellipsoid, pyriform to clavate to narrowly to broadly ellipsoid to rarely inequilateral in face and profile lageniform with pedicels and short to quite long views, terete in end views, apiculate, smooth, necks having obtuse apices, walls thin and walls slightly thickened, subhyaline to pale yellow hyaline in KOH, lacking apparent contents. in KOH, contents not visible or of one to many Lamellar trama hyaline. Pileipellis a cystoderm, scattered guttules. Basidia 22–37 × 7–9 μm, cells 34–55 × 17–37 μm, globose to clavate, tetrasterigmate, walls thin and hyaline in sphaeropedunculate to pyriform and pedicellate KOH, contents granular to no apparent contents. to rarely apedicellate, with a few cells having a Pleurocystidia 35–95 × 13–31 μm, scattered, single short apical mucro, walls thin and hyaline common in abundance, narrowly to lageniform in KOH, contents of brown intracellular pigment, with pedicels and short to quite long necks cells moderately to tightly adhering to one having obtuse apices, walls thin and hyaline in another in crush mounts. Pileus trama hyaline, KOH, lacking apparent intracellular contents, at septate. Stipitipellis a cutis of cylindrical hyphae, times covered with an apical cap of amorphous, 3–28 μm wide, walls thin and hyaline in KOH, mucilaginous material. Cheilocystidia 29–72 × septate, lacking apparent contents. Clamp 11–36 μm, crowded to less abundant, globose to connections absent. sphaeropedunculate to pyriform to clavate to utriform to subcylindrical to narrowly to broadly General description: Pileus 1–3 cm in lageniform with pedicels and short to quite long diameter, hemispherical to broadly conic to necks having obtuse apices, walls thin and convex becoming conic-campanulate to convex hyaline in KOH, lacking apparent contents, then expanded to nearly plane, umbo present or sometimes covered with an apical cap of absent; surface glabrous, moist, rugulose to amorphous, mucilaginous material. Lamellar reticulate at least on disc, hygrophanous, trama convergent, hyaline. Subhymenium sometimes splitting radially in age; cinnamon cellular, hyaline. Pileipellis a cystoderm, cells brown (16 A-12, M & P) to (russet, M & P) when 22–55 × 10–37 μm, globose to young to yellow-brown (5E6–E5, M) to vinaceous sphaeropedunculate to pyriform to rarely brown (Rood’s brown, R) in age, disc darker lageniform and pedicellate to apedicellate, walls (5F6, M); margin faintly striate to striatulate. thin and hyaline in KOH, contents usually of Stipe 2.3–5 cm × 2–5 mm, equal, slender; surface brown intracellular pigment, cells tightly glabrous to slightly fibrillose at base; grayish to adhering to one another in crush mounts. Pileus silvery longitudinally streaked, white to whitish- trama composed of 3–14 μm wide cylindrical olive (12 B-2, M & P) at apex to brown-gray to hyphae, hyaline, septate. Stipitipellis a cutis of yellowish brown (12 E-6, M & P) at base; solid cylindrical hyphae, 2–26 μm wide, walls thin and becoming stuffed then hollow; fragile, basal hyaline in KOH, septate, without apparent tomentum white. Lamellae free, broad, whitish contents. Clamp connections absent. Oleiferous becoming pinkish orange (2 B-8, M & P) to hyphae present. Mi. pinkish brown (3 A-9, M & P); edges entire, concolorous. Lamellulae irregular, numerous. Habit and habitat: Solitary to scattered to Context in pileus white to pale watery brown. gregarious on rotting wood of deciduous Stipe context white. Odor none to variably angiosperms. Sometimes found on soil (Vellinga farinaceous. Taste none to variably farinaceous. 1990). Spore print pinkish brown (12 A-9, M & P). Material examined: CSSR: Moravia, Beskidý, Basidiospores 5.3–7.5 × 4.4–6.6 μm, Q = 1.00– Mionsi near Horný Lomna, ad truncum 48 Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 delapsum Abietis albae, 20.VII.1974. coll. R specific collection information that would be Singer and Kuthan, C5584 (F); Moravia, Forest acceptable as an indication of a type specimen. Preserve Salajka, near Bila, Beskidy, ad truncum Thus, we have designated a specimen of original Fagi sylvaticae, 21.VII.1974, coll. R Singer and material from his herbarium that has been Kuthan, C5624 (F). FRANCE: Forêt de Retz previously labeled as type to serve as the south of Villers-Cotterets (Aisne), 18.VII.1965, lectotype. Since fresh material and notes on the coll. RL Shaffer, RL Shaffer 4226 (MICH as collections examined were limited, the general Pluteus chrysophaeus). U.S.A., ILLINOIS: macroscopic description is a composite of the Shelby Co., near Shelbyville, Hidden Springs available collection data and data modified from State Forest, scattered on hardwood, 23.IX.2006, Homola (1969, 1972 (as Pluteus chrysophaeus coll. AS Methven, Minnis 6-09-23-2 (SIU). (Schaeff. : Fr.) Quél.)). MICHIGAN: Chippewa Co., Whitehouse Landing Rd., on rotten wood (Fagus-Acer woods), The taxonomic problems relating to Pluteus 12.VIII.1963, coll. RL Homola, RL Homola 1847; phlebophorus, Pluteus nanus (Pers. : Fr.) P. RL Homola 1849; RL Homola 1970 (MICH as Kumm., and Pluteus chrysophaeus are long Pluteus chrysophaeus). Emmet Co., Sturgeon standing issues that have been discussed by a Bay, scattered on wood, 14.IX.2007, coll. H myriad of mycologists. Singer (1956), Homola Hallen-Adams, Minnis 7-09-14-1 (SIU). OHIO: (1969, 1972), Orton (1986), and Vellinga (1990) Highland Co., Fort Hill State Memorial, on rotten have summarized the salient points. In short, no wood, 07.VII.1967, coll. WB and VG Cooke, WB type material exists for any of the species and and VG Cooke 38556 (MU as Pluteus sp.). New short circumscriptions lacking any modern York: St. Lawrence Co., Star Lake, 12.VIII., coll. characters are the only means of interpreting the CH Peck, CH Peck, s.n. (designated lectotype of species. Kühner and Romagnesi (1956) and Pluteus admirabilis var. fuscus, NYS). Orton (1960) treated P. chrysophaeus and P. phlebophorus as synonyms with the former using Known distribution: Pluteus phlebophorus P. chrysophaeus as the correct name and the appears to be widespread in the Eastern U.S.A. latter using P. phlebophorus. According to Singer (1956) reported it from New York and Singer (1956), Lange also used the name P. Michigan. Additionally, it is found in Europe chrysophaeus for this taxon. Homola utilized P. (Orton 1986, Vellinga 1990, Breitenbach and chrysophaeus because Ditmar’s illustration of P. Kränzlin 1995) and Asia (Breitenbach and phlebophorus seemed to indicate a more veined Kränzlin 1995). pileus than the North American material he examined (Homola 1969, 1972). However, this Notes: No type material exists for Pluteus character is known to be variable (Orton 1986). phlebophorus (Singer 1956). We concur with To complicate matters, Singer (1956) and Orton Singer (1956) and Homola (1969, 1972) that an (1986) reviewed Fries’ original use of the epithet original plate in Ditmar’s 1817 description chrysophaeus as a variety of Agaricus leoninus provides a reasonable illustration of the species. possessing a yellowish pileus. Although Fries This could be designated as a lectotype, but we later changed his mind and used chrysophaeus have not done so. European mycologists should for a species with a brownish pileus, confusion select a suitable specimen from the topotype to remains and Pluteus phlebophorus is the serve as an epitype. The macroscopic description preferred name (Singer 1956, Orton 1986). of the lectotype of Pluteus admirabilis var. fuscus Vellinga (1990) accepts P. phlebophorus in the was modified from the protologue (Peck 1885) same sense. In accordance with the consensus of and supplemented with observations of the dried these authors, we have chosen to use P. herbarium material. Peck (1885) did not provide phlebophorus for this taxon. Various uses of Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 49

Pluteus chrysophaeus and Pluteus nanus have first study to document the microscopic also been interpreted and employed by Singer characters of Pluteus admirabilis var. fuscus. We (1956), Orton (1986), and Vellinga (1990, 1998). found a cellular pileipellis and numerous A discussion of these is beyond the scope of this narrowly, lageniform pleurocystidia with long, work as it is unclear if either of these taxa are narrow necks. This specimen is typical of our found in the U.S.A. according to any of these concept of Pluteus phlebophorus, and we have interpretations. listed it here as a synonym. Peck (1885) did not provide complete notes about P. admirabilis var. Peck (1885) discussed in his circumscription of fuscus, and we must conclude that he was Pluteus admirabilis var. fuscus that this variety confused by this specimen as he readily admitted may grow with and on the same fallen log as the to having questions about the variation of this typical form. Peck (1885) went on to discuss the group. In part, we feel this was due to the lack of difficulty in distinguishing the species that group detailed microscopic examinations in the near two similar taxa, Pluteus phlebophorus and mycological research of his time. Pluteus leoninus (Schaeff. : Fr.) P. Kumm. Both of these taxa possess a predominantly white The European Pluteus cinereofuscus J.E. Lange colored stipe that may be slightly yellowish at the differs from P. phlebophorus in its more gray to base, and P. phlebophorus sometimes discolors olive colored pileus (Vellinga 1990). In the towards tan, especially at the base in age and U.S.A., Pluteus jamaicensis Murrill, Pluteus upon bruising (Vellinga 1990). Peck (1885) praerugosus Murrill, and Pluteus pulverulentus stated that the stipe of the typical form of Pluteus var. pseudonanus Singer have more globose admirabilis was yellow to yellowish white. shaped basidiospores than P. phlebophorus. Unfortunately, Peck (1885) did not note the color Pluteus pallidus Homola is distinguished by its of the stipe of Pluteus admirabilis var. fuscus. As whitish colored pileus. Pluteus ludovicianus noted above under Pluteus chrysophlebius (Berk. Murrill and Pluteus fulvibadius Murrill are & Ravenel) Sacc. var. chrysophlebius, the correct separated in part by having broader shaped name for the typical form of Pluteus admirabilis, pleurocystidia. the pileus is hygrophanous and sometimes tends to discolor towards darker hues in age. It is Future work should address whether North possible that Peck observed the results of this American isolates and European isolates of phenomenon and chose to recognize dark forms Pluteus phlebophorus are conspecific. Possible with the description of Pluteus admirabilis var. synonymy with Pluteus nanus and Pluteus fuscus. However, it is difficult to know if the pallidus should also be addressed using DNA original material was mixed with the typical form data. or a collection found on its own. Based on our experience, it is not impossible to find more than one Pluteus species growing on the same (17) Pluteus praerugosus Murrill, Mycologia substrate, occasionally with very close proximity 12: 326. 1920. Type citation: “Type collected on a to each other. This could also be the case with dead white oak log in Preston’s Woods, Peck’s concept of the typical form of Pluteus Blacksburg, Virginia, July 16–31, 1920, W. A. admirabilis and P. admirabilis var. fuscus. Murrill.” Fig. 36. Fortunately, microscopic examination can be used to readily separate P. chrysophlebius, P. Diagnostic characters: Pileus brownish; stipe leoninus, and P. phlebophorus as well as Pluteus whitish; cystidia rare; pleurocystidia often fulvibadius Murrill. All of these may be confused cylindrical-clavate to broadly lageniform; if only macroscopic features are used. This is the basidiospores usually globose to subglobose; 50 Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 pileipellis lacking cystidioid elements; KOH, septate, lacking apparent contents. Clamp distribution temperate North America. connections absent.

Selected descriptions and illustrations: Habit and habitat: Gregarious on a dead, Banerjee and Sundberg, Mycotaxon 49: 427-428, dicotyledonous log of white oak (possibly Icon. 428-429, Fig. 29. 1993a. Quercus alba).

Description of the type specimens: Material examined: U.S.A., VIRGINIA: Pluteus praerugosus (holotype) Blacksburg, mostly in oak-chestnut woods with white oak predominating, 16-30.VII.1920, coll. Pileus 3–4 cm in diameter, convex to nearly WA Murrill, WA Murrill, s.n. (holotype of Pluteus plane, slight umbo present in early stages; praerugosus, NY). surface glabrous, very rugose, dry; fuliginous with darker disc; margin long-striate. Stipe 3–4 Known distribution: This species is only cm long, nearly equal; surface glabrous, not represented by the type collection. It is reported twisted; pallid. Lamellae free, crowded, tapering from Virginia, U.S.A. (Murrill 1920). behind, white becoming pinkish; edges entire. Notes: The macromorphological description of Basidiospores 5.7–7.5 × 4.8–7.0 μm, Q = 1.00– the holotype was tailored from the protologue 1.25 (Lm = 6.7 μm, Wm = 6.1 μm, Qm = 1.10), (Murrill 1920). globose, subglobose, broadly ellipsoid to ovate in face and profile views, circular in end views, Banerjee and Sundberg (1993a) provided the only apiculate, smooth, walls somewhat thickened, modern description of the holotype of Pluteus subhyaline to pale yellow in KOH, contents of one praerugosus since it was described by Murrill. to few central guttules or with several sprinkled They considered it to be a synonym of Pluteus smaller guttules giving grainy appearances. nanellus Murrill. Examination of the holotype Basidia 17–33 × 6–9 μm, clavate, tetrasterigmate, did not reveal the presence of the pilocystidial walls thin and hyaline in KOH, with granular elements reported by Banerjee and Sundberg contents or no apparent contents. Pleurocystidia (1993a). Additionally, pleurocystidia were found 33–45 × 15–20 μm, scattered, infrequent, where Banerjee and Sundberg (1993a) did not. broadly lageniform having pedicels and short Finally, the brown pigmented caulocystidia that necks with obtuse apices to somewhat clavate- are characteristic of P. nanellus and its synonyms cylindrical to ellipsoid, often collapsing, walls are lacking. This species should be classified in thin and hyaline in KOH, without visible subsection Eucellulodermini because of its more contents. Cheilocystidia 35–44 × 18–22 μm, or less homogenous pileipellis elements. The rare, subglobose to sphaeropedunculate to condition of the holotype is extremely poor, and pyriform, walls thin and hyaline in KOH, without it is difficult to study. Supplemental material is apparent contents. Lamellar trama hyaline. needed in order to clarify the identity of this Pileipellis a cystoderm, cells 17–40 × 15–23 μm, taxon. The globose to subglobose basidiospores, globose to sphaeropedunculate to pyriform and pleurocystidia, and pileipellis structure are very with or without pedicels, walls slightly thickened close to Pluteus jamaicensis Murrill. Pluteus and hyaline in KOH, often containing light brown praerugosus may very well be a synonym. We intracellular pigment, cells tightly adhering to have tentatively left the two species as separate each other in crush mounts. Pileus trama because of the poor state of knowledge of this hyaline, septate. Stipitipellis a cutis of cylindrical species and the need for additional study of hyphae, 3–18 μm wide, walls thin and hyaline in material from the environs of the type. In the key Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 51 herein, P. praerugosus and P. jamaicensis are slightly sulcate, appearing especially striate dried. distinguished by temperate and tropical Stipe 12–32 × 1–2 mm, equal or tapering distributions, respectively. This is admittedly upwards with occasional slightly bulbous base; rather arbitrary as the only collection of P. surface glabrous; white; basal tomentum white. praerugosus was found in the summer at a site Lamellae free, broad, ventricose, crowded that may indicate a more northern distribution becoming subclose to moderately close, white for P. jamaicensis. becoming pink; edges concolorous. Context in pileus white, thin. Odor none. (18) Pluteus pulverulentus var. pseudonanus Singer, Lloydia 21: 289. 1958 Basidiospores 5.3–7.0 × 5.3–7.0 μm, Q = 1.00– (1959). Type citation: “Argentina: Prov. Salta, 1.08 (Lm = 6.4 μm, Wm = 6.3 μm, Qm = 1.01), Burruyacú, R. Singer T 2986, 17-II-1957 (LIL, globose to occasionally subglobose in face and typus).” Fig. 37. profile views, circular in end views, apiculate, smooth, walls slightly thickened, subhyaline to Diagnostic characters: Pileus brown; stipe pale yellow in KOH, contents not visible or whitish; basidiospores all more or less perfectly variably guttulate. Basidia 17–33 × 6–12 μm, globose in appearance; pileipellis lacking clavate, tetrasterigmate, walls thin and hyaline in cystidioid elements. KOH, lacking apparent contents. Pleurocystidia 33–50 × 13–23 μm, scattered, less than common Selected descriptions and illustrations: in abundance, pyriform to clavate-cylindrical to Murrill, North American Flora 10: 137. 1917; rarely lageniform with pedicels and moderately Singer, Trans. Brit. Mycol. Soc. 39: 209-210, long necks having narrow, obtuse apices, often Icon. 210, Fig. 57. 1956; Smith and Stuntz, collapsing, walls thin and hyaline in KOH, Lloydia 21: 132. 1958; Pegler, Agaric Flora of the without visible intracellular contents to very Lesser Antilles, 323, Icon. 326, Figs. F-K. 1983; rarely filled with brown intracellular pigment. Banerjee and Sundberg, Mycotaxon 49: 428, Cheilocystidia 22–34 × 11–18 μm, crowded, Icon. 428-429, Fig. 30. 1993a (for type variety subglobose to utriform lacking necks to comparison of Pluteus pulverulentus). lageniform with pedicels and moderately long necks having narrow, obtuse apices, walls thin Description of the type specimens: and hyaline in KOH, lacking apparent contents to Pluteus pulverulentus var. pseudonanus rarely filled with brown intracellular pigment, (macroscopic description is composite of data some with an apical cap of amorphous, from holotype and paratypes, microscopic mucilaginous material. Lamellar trama hyaline. description is composite of data from two Subhymenium cellular, hyaline. Pileipellis a paratypes) cystoderm, cells 33–72 × 17–46 μm, globose to sphaeropedunculate to clavate and usually Pileus 12–28 mm in diameter, campanulate- pedicellate, walls thin and hyaline in KOH, convex becoming convex to applanate to slightly usually containing brown intracellular pigment, depressed around the umbo; surface glabrous cells not tightly adhering to one another in crush becoming finely pruinose-velutinous dried under mounts. Pileus trama hyaline, septate. a hand lens, indistinctly to strongly venose, Stipitipellis a cutis of cylindrical hyphae, 3–22 radiate-rugose, or reticulate-scrobiculate on area μm wide, walls thin and hyaline in KOH, septate, around disc; mixture (Saccardo’s umber and without apparent contents to few with brown pinkish buff, R) to (English oak, M & P, 8-C-11), intracellular pigment. Clamp connections absent. disc deep sepia brown or fuscous (bark, M & P, 8- C-11); margin smooth to transparently striate to Habit and habitat: Solitary to scattered on 52 Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 rotten lignicolous substrates of dicotyledons or Singer recognized two varieties, Pluteus earth. It is found in hammocks in the U.S.A. pulverulentus Murrill var. pulverulentus and Pluteus pulverulentus var. pseudonanus, on the Material examined: U.S.A., FLORIDA: Dade basis of spore size with the former having slightly Co., Miami, Matheson Hammock, 28.IX.1942, smaller basidiospores than the latter. Smith and coll. R Singer, F 885 (paratype of Pluteus Stuntz (1958) and Olivia Rodríguez (based on pulverulentus var. pseudonanus, F as Pluteus notes housed with the holotype of Pluteus jamaicensis); Royal Palm State Park, on Bursera pulverulentus, NY) reported a larger spore range (Elaphrium), 27.X.1942, coll. R Singer, F 1307 for the holotype of P. pulverulentus var. (paratype of Pluteus pulverulentus var. pulverulentus than Singer (1956). We feel the pseudonanus, F as Pluteus jamaicensis); on use of varieties is highly questionable. Since we trunk of Ficus, 27.X.1942, coll. R Singer, F 1327 have not examined microscopic characters for the (F as Pluteus jamaicensis). holotypes of either variety, we will leave the two varieties as distinct for now. Known distribution: Pluteus pulverulentus Murrill is known from Argentina (Singer 1958) Two South American taxa, Pluteus eliae Singer and Venezuela (Dennnis 1970) in South America, and Pluteus sapiicola Singer, are similar species the Caribbean (Dennis 1953, Pegler 1983), and classified in stirps Pulverulentus (Singer 1958). Florida, U.S.A. (Singer 1958). It has also been Pluteus eliae differs from P. pulverulentus var. reported from Africa (Horak 1978), but the pulverulentus in having a distinctly sulcate description does not match the material above. margin (Singer 1958). Pluteus sapiicola differs in having brownish fibrils on the stipe (Singer Notes: The holotype was not examined. The 1958). Pluteus pulverulentus var. pulverulentus macromorphological description was assembled is also close to Pluteus jamaicensis Murrill. from the protologue (Singer 1958) and Singer’s However, the latter differs subtly in typically unpublished notes (F). The microscopic having more elongated shapes of lamellar cystidia description is a composite of data from two and basidiospore shapes that are often not paratypes. Three collections of Pluteus perfectly globose in appearance. Other members pseudonanus var. pseudonanus from the Field of stirps Jamaicensis are also separated from P. Museum were found under Pluteus jamaicensis pulverulentus on the basis of basidiospore shape Murrill and were apparently not updated to the (Singer 1958, 1986). correct taxon name. Some discrepancies were found between Singer’s unpublished notes (F), Singer’s publications (1956, 1958), and the (19) Pluteus roseocandidus G.F. Atk., Ann. herbarium labels in regards to locality and Mycol. 7: 373. 1909. Type citation: “C. U. herb., collection dates. In these cases, Singer’s notes No. 18384, on grassy ground, border Cascadilla were given priority followed by publications and woods, Ithaca, N. Y., July 28, 1904, Jackson.” then herbarium labels in the construction of the Fig. 38. specimens examined section. One specimen examined was not an original collection, but its Diagnostic characters: Pileus white; stipe characters matched both of the examined original white; pleurocystidia broadly lageniform to collections, and data for it are not presented utriform to cylindrical-clavate; pileipellis lacking separately under a general description section for cystidioid elements. non-type material. Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 53

Description of the type specimens: globose to sphaeropedunculate to pyriform, walls Pluteus roseocandidus (holotype) thin and hyaline in KOH, without apparent contents, cells strongly adhering to one another Basidiocarps 3–4 cm high. Pileus 2–3 cm in in crush mounts. Hyphal cells immediately diameter, convex becoming expanded, upturned below and connecting to the cystoderm layer at maturity; surface smooth; pure white with somewhat inflated but not interpreted as a older, wet basidiocarps displaying a tinge of rose multilayered pileipellis (see discussion). Pileus similarly to other Pluteus spp.; margin striate. trama hyaline, septate. Stipitipellis a cutis of Stipe 3–4 mm thick, even, occasionally cylindrical hyphae, 3–18 μm wide, walls thin and compressed, fibrous striate; surface smooth hyaline in KOH, septate, without apparent slightly mealy at the apex; white; fragile; basal contents. Clamp connections absent. The type tomentum sometimes hairy, white. Lamellae material is covered with a whitish growth that very slightly adnexed, not very crowded, appears to be an imperfect fungus. elliptical, rounded behind, becoming rose at maturity. Context thin. Habit and habitat: Gregarious on grass covered soil. Basidiospores 6.2–9.2 × 5.3–7.9 μm, Q = 1.00– 1.38 (Lm = 7.4 μm, Wm = 6.2 μm, Qm = 1.19), flesh Material examined: U.S.A., NEW YORK: colored in mass, very few globose, subglobose, Tompkins Co., Ithaca, border Cascadilla Woods, broadly ellipsoid to ellipsoid to mostly ovate in on grassy ground, 28.VII.1904, coll. HS Jackson, face and profile views, circular in end views, 18384 (holotype of Pluteus roseocandidus, CUP). apiculate, smooth, walls slightly thickened, subhyaline to pale yellow in KOH, contents not Known distribution: This species is only visible or of scattered guttules giving grainy known from the holotype collection. It is appearances. Basidia 19–33 × 7–11 μm, clavate, reported from New York, U.S.A. (Murrill 1917). tetrasterigmate, walls thin and hyaline in KOH, without visible contents. Pleurocystidia 44–84 × Notes: The macromorphological description of 15–33 μm, frequent in abundance, narrowly to the holotype was modified from the protologue broadly lageniform or utriform with pedicels and (Atkinson 1909). The observation of attached with necks possessing narrow to quite broad, lamellae seems to be erroneous. obtuse apices to cylindrical-clavate, readily collapsing, walls thin and hyaline in KOH, Atkinson (1909) observed that the pileipellis of without apparent intracellular contents, nearly Pluteus roseocandidus was composed of cellular always covered with an apical cap of amorphous, elements arranged 2–3 layers deep. Homola mucilaginous material. Cheilocystidia 39–66 × (1972) used this feature to separate P. 11–34 μm, moderately abundant, more or less roseocandidus from Pluteus pallidus Homola similarly shaped to pleurocystidia in being even though he seemed to have some question narrowly to broadly lageniform to utriform with about whether or not Atkinson’s observation was pedicels and with long or short necks possessing correct since he had not studied any P. narrow to quite broad, obtuse apices to roseocandidus material. Singer (1977) also cylindrical-clavate, regularly collapsing, walls emphasized the multilayered cellular pileipellis in thin and hyaline in KOH, lacking apparent his key to section Celluloderma taxa having contents, frequently covered with an apical cap of whitish pilei. After examining the structure of amorphous, mucilaginous material. Lamellar the pileipellis of P. roseocandidus, we feel that trama convergent (Atkinson 1909), hyaline. Atkinson’s interpretation of a multilayered Pileipellis a cystoderm, cells 15–42 × 11–36 μm, pileipellis (suprapellis, see Largent et al. 1977) is 54 Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 questionable. First, it is difficult to obtain radial semibulbosus sensu J.E. Lange) should be sections for microscopic viewing that are one cell discussed. Pluteus hololeucus is separated by its layer deep. Because of this problem, adjacent sulcate pileus margin and more globose shaped cells in the pileipellis may seem to be part of a basidiospores (Singer 1977; Singer’s unpublished multilayered structure when they are merely notes, F). Pluteus inquilinus is reported to have oriented incorrectly after preparing the material caulocystidia (Vellinga 1990). This character for viewing. Secondly, pileipellis cells in section separates it from the similar P. roseocandidus. Celluloderma are often quite different in size. In this case a smaller cell positioned next to a larger Most of the species of section Celluloderma with cell may seem to be part of another layer even whitish colored pilei are only known from a though it is not. Finally, we have noticed a handful of collections. Many more are needed if tendency for the cells connecting to the terminal these taxa are to be well understood. pileipellis elements in Pluteus to become shorter and more inflated. This occurs in all sections of Pluteus section Celluloderma taxa Pluteus. In section Celluloderma this tendency is extralimital to the scope of this study greater in subsection Eucellulodermini than subsection Mixtini. These subterminal cells may Pluteus podospileus Sacc. & Cub., Sylloge be interpreted as a multilayered pileipellis Fungorum 5: 672. 1887. Type citation: “Hab. ad (suprapellis) or perhaps even a rudimentary truncos Batheaston Britanniae.” Fig. 39. subpellis (see Largent et al. 1977). However, it is ≡ Pluteus nanus var. podospileus (Sacc. & contention here that the pileipellis is composed of Cub.) Rick, Lilloa 3: 444. 1938. a single layer of cells just like it is in every other = Pluteus minutissimus Maire, Publ. Inst. section Celluloderma taxon that we have seen. Bot. 3: 94. (1937). Additionally, these inflated subterminal cells are ≡ Pluteus psichriophorus var. not consistently present and many terminal minutissimus (Maire) Singer, Trans. Brit. Mycol. pileipellis elements lack them. This provides Soc. 39: 214. 1956. ad int. (as Pluteus additional support for the opinion that they are psychriophorus var. minutissimus). This is a not truly part of another distinct layer. Pluteus nom. inval. pallidus as well as many other related taxa also ≡ Pluteus podospileus Sacc. & Cub. f. possesses similar subterminal cells. Given the minutissimus (Maire) Vellinga, in Vellinga & importance of pileipellis anatomy in Pluteus Schreurs, Persoonia 12: 362 (1985). taxonomy, a more detailed examination of the = Pluteus minutissimus Maire f. major pileus trama and pileipellis elements is warranted Kühner, in Kühner and Romagnesi, Bull. Soc. in future studies. Mycol. France 72: 182. 1956.

Pluteus pallidus G.F. Atk., the only other species Types and typifications: To our knowledge, from section Celluloderma with a whitish pileus no original material for Pluteus podospileus known from North America, is easily separated exists. Cooke’s incorrectly identified material from P. roseocandidus in having more narrowly from Europe that led Saccardo and Cuboni to lageniform pleurocystidia with long, narrow name the fungus was not preserved (Orton 1960). necks than the broader shaped pleurocystidia of P. roseocandidus. Two other species classified by Diagnostic characters: Pileus small; brownish Singer (1986) in stirps Roseocandidus, Pluteus colored; stipe white; covered at least in part with hololeucus Singer and Pluteus inquilinus dark brown fibrils. Microscopically, Romagn. (formerly known as Pluteus pleurocystidia broadly lageniform to utriform; alborugosus Kühner & Romagn. and Pluteus pileipellis includes cystidioid elements having Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 55 setoid shapes; caulocystidia containing brown visible or of one to many scattered guttules giving intracellular pigment. grainy appearances. Basidia 20–28 × 6–9 μm, clavate, tetrasterigmate, walls thin and hyaline in Selected descriptions and illustrations: KOH, contents granular or agranular. Orton, British Fungus Flora: Agarics and Boleti, Pleurocystidia 35–57 × 12–23 μm, moderately Vol. 4, Pluteaceae: Pluteus and Volvariella, 58- abundant, broadly lageniform to utriform with 59, Icon. 94-95 and 96-97, Figs. 39-40 and 64- pedicels and short necks having broad, obtuse 68. 1986; Vellinga, Pluteus, In: Bas et al., Flora apices, walls thin and hyaline in KOH, without Agaracina Neerlandica, Vol. 2, 45-46, Icon. 46, visible contents. Cheilocystidia 35–65 × 11–26 Fig. 25. 1990 (as Pluteus podospileus). μm, crowded, subglobose to pyriform to clavate- cylindrical, walls thin and hyaline in KOH, Breitenbach and Kränzlin, Fungi of Switzerland, lacking discernable intracellular contents to Vol. 4, 128, Icon. 128-129, photograph and Figs. rarely with brown intracellular pigment. A-E. 1995; (as Pluteus podospileus f. Lamellar trama convergent, hyaline. podospileus). Subhymenium cellular, hyaline. Pileipellis a cystoderm, cells 33–110 × 14–30 μm, elements Breitenbach and Kränzlin, Fungi of Switzerland, sphaeropedunculate to pyriform to broadly Vol. 4, 128, Icon. 128-129, photograph and Figs. lageniform to setoid with tapered, obtuse apices A-E. 1995 (as Pluteus podospileus f. and all pedicellate, walls thin, nearly always filled minutissimus). with brown intracellular pigment, cells weakly adhering to each other in crush mounts. Pileus Orton, British Fungus Flora: Agarics and Boleti, trama hyaline, septate. Stipitipellis a cutis of Vol. 4, Pluteaceae: Pluteus and Volvariella, 59- cylindrical hyphae, 3–21 μm wide, walls thin and 60. 1986. (as Pluteus minutissimus). hyaline in KOH, septate, without apparent contents. Caulocystidia abundant, in fascicles, General description: Pileus 22–24 mm in terminal elements cylindrical to clavate with diameter, convex, umbonate with broad, obtuse hyphae being 12–19 μm wide, walls thin and and not very low umbo to subumbonate; surface hyaline in KOH, filled with brown intracellular smooth, not venose-rugose, velutinous, densely pigment. Clamp connections absent. Oleiferous punctulate to spinulose-flocculose under a lens; hyphae present. deep spadiceous, unicolorous; margin transparently striate, not so when dried. Stipe Habit and habitat: Solitary to scattered to 23–38 × 1.5–3 mm, tapering towards apex; gregarious on dead, deciduous wood of surface densely speckled-punctate-fibrillose with angiosperms (Vellinga 1990) to sometimes on dark fibrils the length of the stipe; ground pallid; soil (Vellinga 1990). hollow. Lamellae free, broad, ventricose, close to crowded, white becoming pink; edges pallid to Material examined: CSSR: Moravia, 6 km occasionally sepia at margin. Context white. from Ostrava, Forest Preserve Komora, near Odor none. Silherovice, 23.VII.1974, coll. Singer and Kuthan, C5647 (F); ad truncos Fagi, 23.VII.1974, coll. R Basidiospores 5.3–6.6 × 4.4–5.3 μm, Q = 1.00– Singer and Kuthan, C5642 (F 1018794) (F as 1.40 (Lm = 5.8 μm, Wm = 4.7 μm, Qm = 1.23), Pluteus minutissimus f. major); ad truncum globose, broadly ellipsoid, ellipsoid to ovate in delapsum Fagi sylvatticae, 23.VII.1974, coll. R face and profile views, circular in end views, Singer and Kuthan, C5642 (F 1018806) (F as apiculate, smooth, walls slightly thickened, Pluteus minutissimus f. major). Sweden: subhyaline to pale yellow in KOH, contents not Blekinge, Karlskrona, the cemetery of Tyska 56 Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107

Kyrkan, in mossy lawn, 24.IX.1946, coll. S podospileus has a European distribution (see Lundell, S Lundell 2541 (MICH as Pluteus discussion of Pluteus seticeps var. cystidiosus). phlebophorus). Additionally, the pleurocystidia of P. podospileus are typically more lageniform in shape than those Known distribution: Pluteus podospileus is of P. seticeps var. cystidiosus. However, more found in Europe (Orton 1986, Vellinga 1990, observations need to be made before this Breitenbach and Kränzlin 1995), and it has also variation is confirmed. None of the North been reported from Africa (Vellinga 1990) and American material near P. podospileus has stipes Asia (Takehashi and Kasuya 2009). with ornamentation along the majority of the length. This may be another important Notes: Type material is not available for P. distinguishing feature. podospileus. It is the responsibility of mycologists in Europe to select a suitable Pluteus romellii (Britzelm.) Lapl., Dictionnaire collection from the environs of the type to serve Iconographique des Champignons Supérieures, as a neotype. 533. 1894. Fig. 40. ≡ Agaricus romellii Britzelm., The taxonomic opinions and synonyms relating Hymenomyceten aus Sudbayern, VIII: 5. 1891 to Pluteus podospileus have been summarized by (basionym). Type citation: Unable to obtain the Orton (1986), Vellinga and Schreurs (1985), and protologue. Vellinga (1990) and the synonyms used here are = Agaricus nanus var. lutescens Fr., Epicrisis based on these works. The classification scheme Systematis Mycologici, 141. 1838. first used by Grauwinkel and Meusers (1984) ≡ Pluteus nanus var. lutescens (Fr.) P. synonymizes Pluteus podospileus and Pluteus Karst., Rysslands, Finlands och den minutissimus and related synonyms into one Skandinaviska Halföns. Hattsvampar, 256. 1879. taxon. If one considers the forms of this species ≡ Pluteus nanus subsp. lutescens (Fr.) employed by Vellinga (1990), the material Konrad & Maubl., Icones Selectae Fungorum 6: studied corresponds to Pluteus podospileus Sacc. 55. 1930. & Cub. f. podospileus, an autonym, because of the ≡ Pluteus lutescens (Fr.) Bres., Iconogr. stipe ornamentation along a large portion of its Mycol. 11: 544. 1929. length. = Pluteus sternbergii Velen., České Houby, 610. 1921. Numerous taxa discussed under Pluteus seticeps (G.F. Atk.) Singer var. seticeps are Types and typifications: No existing type morphologically similar to P. podospileus. Many specimen for Pluteus romellii is available. See of these are poorly known and Singer discussion. (unpublished notes, F) used variable characters such as acuteness in the shape of pileipellis Diagnostic characters: Macroscopically, elements, stipe ornamentation, and geographic pileus uniformly brown pigmented; stipe region from which the species were described to yellowish. Microscopically, pleurocystidia separate taxa. More studies are needed in order broadly shaped in relation to length; to clarify the identity of these taxa. basidiospores not predominantly globose; pileipellis lacking cystidioid elements. Pluteus seticeps var. seticeps is differentiated from P. podospileus by its lack of pleurocystidia. Selected descriptions and illustrations: Pluteus seticeps var. cystidiosus Minnis & Sundb. Orton, British Fungus Flora: Agarics and Boleti, has a North American distribution while P. Vol. 4, Pluteaceae: Pluteus and Volvariella, 51- Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 57

52, Icon. 88-89 and 96-97, Figs. 13-17 and 61. 12–36 μm, crowded, subglobose to pyriform to 1986; Vellinga, Pluteus, In: Bas et al., Flora cylindrical-clavate with pedicels and broad, Agaracina Neerlandica, Vol. 2, 48, Icon. 49, Fig. obtuse apices, walls thin and hyaline in KOH, 28. 1990; Breitenbach and Kränzlin, Fungi of lacking apparent contents, at times with an apical Switzerland, Vol. 4, 130, Icon. 130-131, cap of amorphous, mucilaginous material. photograph and Figs. A-D. 1995. Lamellar trama convergent, hyaline. Subhymenium cellular, hyaline. Pileipellis a General description: Pileus 12–80 mm in cystoderm, cells 20–61 × 15–40 μm, globose to diameter, convex to broadly conical with obtuse sphaeropedunculate to rarely irregularly clavate apices becoming plano-convex to applanate, and pedicellate to apedicellate, walls thin and usually with low umbo; surface usually rugose at hyaline in KOH, containing dark brown disc and venose towards margin to glabrous, intracellular pigment, cells tightly adhering to sometimes rimose with white ground showing one another in crush mounts. Pileus trama giving a striate appearance; dark brown to brown hyaline, septate. Stipitipellis a cutis of cylindrical to yellowish brown; margin wavy-lobed, hyphae, 3–23 μm wide, thin-walled, septate, frequently translucently striate. Stipe 14–90 × without apparent contents. Clamp connections 1.5–9 mm, equal to tapered above; surface absent. Oleiferous hyphae present. Mi. smooth or innately yellow-fibrillose; yellow, chrome-yellow, apex paler to white; solid to Habit and habitat: Solitary to gregarious on fistulose to hollow; basal tomentum white. hardwood, wood chips, sawdust, and soil in Lamellae free, broad, ventricose, more or less hardwood and mixed conifer-hardwood forests crowded, whitish to yellow becoming pink; edges (Orton (1986), Vellinga (1990), and Breitenbach even to minutely flocculose-denticulate, and Kränzlin (1995)). concolorous. Context in pileus hygrophanous, brownish to gray yellow to greenish yellow moist, Material examined: FRANCE: Forêt ď pallescent to white to cream dried. Stipe context Halatte, near Villers-St. Frambourg (Oise), on yellow to white. Odor indistinct to sweet to piece of deciduous wood, 10.VIII.1965, coll. RL acidulous. Taste not distinctive to mild. Shaffer, RL Shaffer 4525 (MICH as Pluteus lutescens). SCOTLAND: Culbin Forest, near Basidiospores 6.2–7.9 × 4.8–6.6 μm, Q = 1.07– Forres, 8.IX.1975, coll. RL Shaffer, RL Shaffer 1.33 (Lm = 6.9 μm, Wm = 5.7 μm, Qm = 1.22), 7010 (MICH as Pluteus lutescens). subglobose, broadly ellipsoid, ellipsoid to ovate in face and profile views, circular in end views, Known distribution: Pluteus romellii is apiculate, smooth, walls slightly thickened, known from Europe (Orton 1986, Vellinga 1990, subhyaline to pale yellow in KOH, contents not Breitenbach and Kränzlin 1995). It has also been visible or of one to many scattered guttules giving reported from Africa (Vellinga 1990, Breitenbach grainy appearances. Basidia 22–29 × 7–9 μm, and Kränzlin 1995), Mexico (Rodríguez and clavate, tetrasterigmate, walls thin and hyaline in Guzmán-Dávalos 2001), and South America as a KOH, contents granular to no apparent contents. suspected introduction by Singer (1958). The Pleurocystidia 52–62 × 14–30 μm, scattered, collections from Mexico may be conspecific with common in abundance, predominantly more or Pluteus fulvibadius Murrill. less cylindrical-clavate with pedicels and broad, obtuse apices, walls thin and hyaline in KOH, Notes: Since no fresh material or notes on lacking apparent intracellular contents, some examined European collection were available, the covered with an apical cap of amorphous, general macroscopic description is a composite of mucilaginous material. Cheilocystidia 23–61 × 58 Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 the data presented by Orton (1986) and Vellinga Pluteus campanulatus Murrill, North (1990). American Flora 10: 131. 1917. Type citation: “Type collected on rotten wood in wet woods at The taxonomy of Pluteus romellii, a taxon more Redding, Connecticut, July, 1902, L. M. widely known in the past as Pluteus lutescens or Underwood & F. S. Earle 655 (herb. N. Y. Bot. Pluteus nanus var. lutescens has been discussed Gard.).” Fig. 41. at length in the literature despite the lack of type =? Agaricus longistriatus Peck, Rep. (Annual) collections (Singer 1956, Vellinga and Schreurs New York State Mus. Nat. Hist. 30: 40. 1878. 1985, Orton 1986). The synonyms listed in the ≡? Pluteus longistriatus (Peck) Peck, Rep. nomenclatural portion are based on Vellinga and (Annual) New York State Mus. Nat. Hist. 38: 137. Schreurs (1985) and Orton (1986). Long 1885. tradition among mycologists in Europe accepts this species as described above (Singer 1956, Diagnostic characters: Macroscopically, Orton 1986). A plate accompanying the original pileus brown; campanulate; with long striations description by Britzelmayr (Orton 1986) could to the disc; stipe white. Microscopically, cystidia serve as the lectotype, but no European authors fusoid shaped; pileipellis composed of elongate have designated it as such. We have not done so. hyphae with brown intracellular pigment. It is the responsibility of European workers to select an appropriate specimen from the topotype Selected descriptions and illustrations: to serve as an epitype for the purpose of Smith and Stuntz, Lloydia 21: 119-120. 1958; nomenclatural stability. Banerjee and Sundberg, Mycotaxon 49: 418, Icon. 420-421, Fig. 7. 1993a. The European Pluteus splendidus A. Pearson is related to P. romellii and differs in its bicolored Description of the type specimens: pileus with both yellow and brown hues. Vellinga Pluteus campanulatus (holotype) and Schreurs (1985) consider P. splendidus to be a synonym because the preserved material Pileus 3 cm in diameter, campanulate, obtuse; designated as the lectotype of P. splendidus lacks surface glabrous; pale-pinkish-fawn-colored; a bicolored aspect and the pileipellis elements are margin striate to disc; subtranslucent; delicate. uniformly filled with brown pigment. Two other Stipe 3–5 cm x 2–3 mm, tapered slightly species, Pluteus galeroides P.D. Orton and upwards; surface glabrous; pallid or whitish; Pluteus xanthophaeus P.D. Orton, differ in pileus hollow; base discoid, attached to mycelial mat. coloration and a narrow type of pleurocystidia. Lamellae free, narrow, crowded, watery -white The Asian Pluteus flavipes Petch, a poorly known becoming pink. species, is also similar in appearance, but it differs by its lighter colored pileus, more globose Basidiospores 6.2–7.9 × 4.8–6.6 μm, Q = 1.00– basidiospores, and smaller size. The South 1.36 (Lm = 6.8 μm, Wm = 5.9 μm, Qm = 1.16), American Pluteus globiger Singer and Pluteus globose, subglobose, broadly ellipsoid, ellipsoid xanthopus Singer are reputed to differ in part by to ovate in face and profile views, circular in end the possession of a large percentage of views, often collapsed, apiculate, smooth, walls geometrically globose basidiospores. The North slightly thickened, subhyaline to pale yellow in American taxon, Pluteus fulvibadius, discussed KOH, without visible contents. Lamellar trama above differs in the shape of the pleurocystidia. hyaline. Pileipellis more or less a cutis with erect to appressed filamentous, cylindrical hyphae, Taxa uncertain or excluded from Pluteus walls thin and hyaline in KOH, sometimes filled section Celluloderma with a fuscous intracellular pigment. Pileus Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 59 trama hyaline. Clamp connections absent. accompanying the specimen, the long striations Hymenium does not revive sufficiently to to the disc, the delicate, thin nature of adequately allow for effective character basidiocarp, the white stipe, and the fusoid description, and no other characters were able to cystidia observed by Banerjee and Sundberg be observed. (1993a) strongly suggests that this species is conspecific with Pluteus longistriatus as Habit and habitat: Solitary on rotten wood in interpreted by numerous North American wet woods. mycologists. Because of the inability to observe elements in the hymenium, questions about Material examined: U.S.A., CONNECTICUT: synonymy remain unanswered. More collections Redding, on rotten wood in wet woods, from the locality of the type in Redding, 24.VII.1902., coll. LM Underwood and FS Earle, Connecticut are needed if this taxon is to be well LM Underwood and FS Earle 655 (holotype of known. Pluteus campanulatus, NY).

Known distribution: This species is only Pluteus tortus Lloyd, Mycological Notes No. 2: known from the type collection. It is reported 15. 1899. Type citation: None but a mention of a from Connecticut, U.S.A. (Murrill 1917). single specimen collected in the vicinity of Cincinnati, OH, USA. Fig. 42. Notes: The macromorphological description of the holotype was constructed from the protologue Types and typifications: (Murrill 1917). Type: Icon. Pluteus tortus (Lloyd Library and Smith and Stuntz (1958) studied the holotype and Museum)—Lectotype designated here. reported difficulties in examining the hymenium. They also reported that the pileipellis was made Diagnostic characters: Pileus brown; up of pedicellate-vesiculose to elliptic cells (Smith rugulose. Stipe white. and Stuntz 1958). Banerjee and Sundberg (1993a) found similar pileipellis elements to Selected descriptions and illustrations: those described by Smith and Stuntz (1958) as Murrill, North American Flora 10: 134. 1917. well as fusoid lamellar cystidia. Because of the state of the type, Singer (1956) considered this Description of the type specimens: taxon to be incertae sedis. In Singer’s Pluteus tortus (original material) unpublished notes (F) on Pluteus section Hispidoderma, he observed that the holotype had Pileus 3 cm in diameter, convex to plane, a filamentous, hyphal pileipellis, but the umbonate, regular; surface conspicuously condition of the type did not allow him to observe rugulose; brownish, umbo darker; margin striate, any lamellar characters. Hymenial characters in entire. Stipe 5 cm x 3–4 mm, equal, curved, the holotype could not be observed due to poor innately striate; surface glabrous; white; solid. revival of the hymenium. However, no globose to Lamellae free, crowded, salmon colored. elliptical cells in the pileipellis were found that would warrant inclusion in section Celluloderma. Habit and habitat: Caespitose. More elongate hyphae in the pileipellis indicate that this species should be classified in section Known distribution: This species is only Hispidoderma. The pale brown color of the known from the type locality in Ohio. campanulate pileus described in the notes 60 Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107

Notes: The macromorphological description of surface smooth, glabrous; snow-white. Lamellae original material was modified from Murrill free, broad, ventricose, subcrowded, white (1917). becoming salmon-colored; edges entire and slightly whitish-pubescent. No specimens are currently available, and none were found in the Lloyd collection at the U.S. Basidiospores 6.6–9.7 × 5.3–7.0 μm, Q = 1.06– National Fungus Collections (BPI). Notes by J.A. 1.33 (Lm = 7.3 μm, Wm = 6.1 μm, Qm = 1.20), Stevenson (BPI) state that it was missing when subglobose, ovate, broadly ellipsoid to ellipsoid in Lloyd’s materials came to BPI. A photograph that face and profile views, circular in end views, was part of the original material is designated as sometimes collapsing, apiculate, smooth, walls the lectotype. The scant information on this slightly thickened, subhyaline to pale yellow in species strongly suggests that this may represent KOH, contents often of one to several scattered Pluteus phlebophorus. However, Pluteus oil drops giving grainy appearances or less thomsonii (Berk. & Broome) Dennis, another commonly not visible. Basidia 15–20 × 7–9 μm, relatively common species in the U.S.A., may also clavate, tetrasterigmate, walls thin and hyaline in have a rugulose surface or one with prominent KOH, contents granular or lacking. raised reticulations. Since it is not possible to Pleurocystidia 39–68 × 12–24 μm, frequent, verify the identity of this fungus with clavate to narrowly cylindrical to narrowly or observations of microscopic characters, we are broadly lageniform with pedicels and short to listing it as uncertain. long necks with obtuse apices, walls thin and hyaline in KOH, lacking visible intracellular Pluteus umbrinidiscus Murrill, North contents or with brown intracellular pigment, at American Flora 10: 130. 1917. Type citation: times covered with amorphous, mucilaginous “Type collected on a dead log at Lake Placid, material. Cheilocystidia not observed. Lamellar Adirondack Mountains, New York, July 17–29, trama hyaline. Pileipellis more or less a cutis 1912, W. A. & Edna L. Murrill (herb. N. Y. Bot. with erect to appressed filamentous, cylindrical Gard.).” Fig. 43. hyphae, walls thin and hyaline in KOH, filled with brown intracellular pigment. Terminal Selected descriptions and illustrations: segments of pileipellis 15–22 μm wide, inflated, Banerjee and Sundberg, Mycotaxon 49: 432-433, cylindrical to broadly lageniform with obtuse to Icon. 430-431, Fig. 37. 1993a (as Pluteus rarely short mucronate apices. Pileus trama umbrinidiscus). hyaline, septate. Clamp connections not seen in examined material. Singer, Trans. Brit. Mycol. Soc. 39: 152. 1956 (as Pluteus avellaneus). Habit and habitat: Solitary on a dead log.

Description of the type specimens: Material examined: U.S.A., NEW YORK: Lake Pluteus umbrinidiscus (holotype) Placid, on log, 17-29.VII.1912, coll. WA Murrill and EL Murrill, WA Murrill and EL Murrill, s.n. Pileus 2.5 cm in diameter, convex, not fully (holotype of Pluteus umbrinidiscus). expanded, slightly umbonate; surface hygrophanous, glabrous, appearing Known distribution: This species is only subtomentose; avellaneous-umbrinous, umbo represented by the type collection. It is known umbrinous; margin entire, striate for 7–8 mm, from New York, U.S.A. (Murrill 1917). paler. Stipe 5cm x 3 mm, cylindrical, equal; Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 61

Notes: The macromorphological description of from the Mycological Society of America and the the holotype was modified from the protologue James E. Ozment Award from SIUC. (Murrill 1917). Literature cited Banerjee and Sundberg (1993a) reported that the Atkinson, G. F. 1902. Preliminary notes on some pileipellis of the holotype consisted of primarily new species of fungi. Journal of Mycology 8: 110– vesiculose-pedicellate cells with the occasional 119. doi:10.2307/3752544 clavate-ventricose cell. They also incorrectly listed the type specimen, noting a specimen from Atkinson, G. F. 1909. Preliminary notes on some Unaka Springs, Tennessee (Banerjee and new species of Agaricaceae and Clavaria. Sundberg 1993a). Smith and Stuntz (1958) did Annales Mycologici 7: 365–376. not examine the holotype in their study of American types. Singer (1956) did not publish Banerjee, P. and W. J. Sundberg. 1991. data on the type, but stated that it was identical Observations on basidiospore germination and to Pluteus avellaneus Murrill, a taxon with the tissue culture growth of some Pluteus species same topotype. Observations on the pileipellis (Pluteaceae, Agaricales). Transactions of the revealed a more or less filamentous cuticle with Illinois State Academy of Science, Supplement to inflated terminal segments. No clamp Vol. 84: 33. (Abstr.). connections or apical appendages on the cystidia were observed in the basidiocarp. Banerjee, P. 1992. A Systematic and Phylogenetic Micromorphological characters of the stipe were Study of the Genus Pluteus with Special not observed. Because of the nature of the Reference to Section Pluteus. Doctoral cuticle, this species should be classified in Pluteus Dissertation. Southern Illinois University section Hispidoderma. The first author has not Carbondale, Carbondale. 141 p. studied the type of Pluteus avellaneus. Thus, synonyms or diagnostic characters for this fungus Banerjee, P. and W. J. Sundberg. 1993a. are not suggested. Reexamination of Pluteus type specimens: Types housed at the New York Botanical Garden. Mycotaxon 49: 413–435. Acknowledgements: This work represents a portion of the Minnis doctoral dissertation Banerjee, P. and W. J. Sundberg. 1993b. submitted to Southern Illinois University Preliminary observations on germination of Carbondale in 2008. We thank the institutions Pluteus basidiospores. Mycologia 85: 811–813. and people who made available materials for this doi:10.2307/3760614 study, especially Joe Ammirati, Meredith Blackwell, Dennis Desjardin, Patrick Leacock, Berkeley, M. J. and C. E. Broome. 1871. The fungi David McLaughlin, Andy Methven (also a of Ceylon (Hymenomycetes, from Agaricus to generous and dedicated committee member), Cantharellus). Journal of the Linnean Society, Greg Mueller, and Patricia Rogers. Christian Botany 11: 494–567. Feuillet is warmly credited for provision of the Latin diagnoses. Gratitude is also extended to Berkeley, M. J. and C. E. Broome. 1876. Notices the reviewers of this article and Joe Ammirati of British fungi. Annals and Magazine of natural and Else Vellinga for their suggestions. Financial history, including zoology, botany, and geology support for this work was provided by the IV 17:129–145. Alexander H. and Helen V. Smith Research Fund 62 Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107

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Ridgway, R. 1912. Color Standards and Color Singer, R. 1969. Mycoflora Australis. Beihefte Nomenclature. Published by the author, Nova Hedwigia 29: 1–405. Washington, D.C. 43 p., 53 pl. Singer, R. 1973. Diagnoses fungorum novorum Rodríguez, O. and L. Guzmán–Dávalos. 1999. agaricalium. III. Beihefte zur Sydowia 7: 1–106. Nuevos registros del género Pluteus Fr. (Pluteaceae) en México. Documents Singer, R. 1977. Amerikanische und asiatische Mycologiques 29: 67–78. Agaricales, die in Europa und Nordafrika vorkommen. Zeitschrift für Pilzkunde 43: 119– Rodríguez, O. and L. Guzmán–Dávalos. 2001. 130. Clave dicotómica de las especies del género Pluteus Fr. (Pluteaceae) conocidas de la region de Singer, R. 1986. The Agaricales in Modern Nueva Galicia y algunas areas aledañas, México. Taxonomy. 4th ed. Koeltz Scientific Books, Acta Botanica Mexicana 57: 23–36. Koenigstein. 981 p.

Rodríguez, O., L. Guzmán–Dávalos and E. Horak. Singer, R. 1989. New taxa and new combinations 2008. Pluteus neotropicalis (Pluteaceae, of Agaricales (Diagnoses fungorum novorum Agaricales), a new species from tropical- agaricalium IV). Fieldiana Botany 21: 1–133. subtropical Mexico. Mycotaxon 103: 273–278. Smith, A. H. 1949. Mushrooms in Their Natural Singer, R. 1956. Contributions towards a Habitats. Sawyers, Portland. 626 p. monograph of the genus Pluteus. Transactions of the British Mycological Society 39: 145–232. Smith, A. H. and D. E. Stuntz. 1958. Studies on doi:10.1016/S0007-1536(56)80001-6 the genus Pluteus I. Redescriptions of American species based on a study of type specimens. Singer, R. 1958 (1959). Monographs of South Lloydia 21: 115–135. American Basidiomycetes, especially those of the east slope of the Andes and Brazil. I. The genus Stuntz, D. E. 1977. How to Identify Mushrooms to Pluteus in South America. Lloydia 21: 195–299. Genus IV: Keys to Families and Genera. Mad River Press, Eureka. 94 p. Singer, R. 1959. Contributions towards a monograph of the genus Pluteus. II. Transactions Takehashi, S. and T. Kasuya. 2009. Pluteus of the British Mycological Society 42: 223–226. magnus and Pluteus podospileus f. podospileus, doi:10.1016/S0007-1536(59)80031-0 two agaric species new to Japan. Mycoscience 50: 74–77. doi:10.1007/s10267-008-0446-0 Singer, R. 1961. Monographs of South American Basidiomycetes especially those of the east slope Vellinga, E. C. 1988. Glossary. 54–64, in Bas C., of the Andes and Brazil. IV. Inocybe in the Th. W. Kuyper, M. E. Noordellos and E. C. Amazone region with a supplement to part I Vellinga (eds.), Flora Agaricina Neerlandica. Vol. (Pluteus in South America). Sydowia 15: 112–132. 1. A.A. Balkema, Rotterdam.

Singer, R. 1963. Notes on secotiaceous fungi: Vellinga, E. C. 1990. Glossary. 6–11 and Pluteus. Galeropsis and Brauniella. Proceedings, 31–55, in Bas C., Th. W. Kuyper, M. E. Koninklijke Nederlandse Akademie van Noordeloos and E. C. Vellinga (eds.), Flora Wetenschappen. Series C, biological and medical Agaricina Neerlandica. Vol. 2. A.A. Balkema, sciences 66: 106-117. Rotterdam. Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 65

Vellinga, E. C. 1998. Tricks to identify Pluteus Wartchow, F., V. G. Cortez and G. Coelho. 2004. species. Coolia 41: 74–77. Pluteus thomsonii (Pluteaceae), a northern agaric found in South America. Mycotaxon 89: 349– Vellinga, E. C. and J. Schreurs. 1985. Notulae ad 353. floram agaricinam Neerlandicam-VIII. Pluteus Fr. in West Europe. Persoonia 12: 337–373. 66 Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107

Fig. 1. Pluteus eugraptus (Berk. & Broome) Sacc. All illustrations AHS 63525. A. Basidiospores. B. Basidium. C. Pleurocystidia. D. Cheilocystidia. E. Caulocystidia. F. Pileipellis elements. Scale bars are 10 μm for all. Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 67

Fig. 2. Pluteus seticeps (G.F. Atk.) Singer var. seticeps. Basidiocarp of NAMA 2007-007. This image is modified from the original (provided by courtesy of Patrick Leacock) that is part of the North American Mycological Association Voucher Collection Project. Scale bar is approximately 1 cm. 68 Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107

Fig. 3. Pluteus seticeps (G.F. Atk.) Singer var. seticeps. All illustrations 9664 (holotype of Leptonia seticeps G.F. Atk.). A. Basidiospores. B. Basidia. C. Cheilocystidia. D. Pileipellis elements. Scale bars are 10 μm for all. Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 69

Fig. 4. Pluteus seticeps (G.F. Atk.) Singer var. seticeps. All illustrations 9724 (original material of Leptonia seticeps G.F. Atk.). A. Basidiospores. B. Basidia. C. Cheilocystidia. D. Caulocystidia. E. Pileipellis elements. Scale bars are 10 μm for all. 70 Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107

Fig. 5. Pluteus seticeps (G.F. Atk.) Singer var. seticeps. All illustrations WA & EL Murrill 73 (holotype of Pluteus nanellus Murrill). A. Basidiospores. B. Basidium and basidiole. C. Pileipellis elements. Scale bars are 10 μm for all. Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 71

Fig. 6. Pluteus seticeps (G.F. Atk.) Singer var. seticeps. A.–B. Basidiospores. A. DED 4634. B. HD Thiers 36151. C.–D. Basidium. C. DED 4634. D. HD Thiers 36151. E. Cheilocystidia, DED 4634. F. Caulocystidia, DED 4634. G.–H. Pileipellis elements. G. DED 4634. H. HD Thiers 36151. Scale bars are 10 μm for all. 72 Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107

Fig. 7. Pluteus seticeps var. cystidiosus Minnis & Sundb. A. Basidiospores, RL Homola 1340 (holotype). B. Basidium, RL Homola 1340. C.–D. Pleurocystidia. C. RL Homola 1340. D. AH Smith 39109. E.–F. Cheilocystidia. E. RL Homola 1340. F. AH Smith 39109. G.–H. Caulocystidia. G. RL Homola 1340. H. AH Smith 39109. I. Pileipellis elements, RL Homola 1340. Scale bars are 10 μm for all. Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 73

Fig. 8. Pluteus thomsonii (Berk. & Broome) Dennis. A. Basidiospores, N5648. B. Basidia, N5648. C.–E. Pleurocystidia. C. N5648. D. AH Smith 1458. E. HD Thiers 33092. F.–G. Cheilocystidia. F. N5648. G. AH Smith 1458. H.–I. Caulocystidia. H. N5648. I. AH Smith 1458. J. Pileipellis elements, N5648. Scale bars are 10 μm for all. 74 Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107

Fig. 9. Pluteus aurantiorugosus (Trog) Sacc. Basidiocarps of MGW 6-29-63-N1. Photograph associated with collection provided by courtesy of David McLaughlin. Largest basidiocarp measured approximately 5.2 cm in pileus diameter. Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 75

Fig. 10. Pluteus aurantiorugosus (Trog) Sacc. All illustrations CUP-A-018770 (designated lectotype of Pluteus caloceps G.F. Atk.). A. Basidiospores. B. Basidium. C. Pleurocystidia. D. Cheilocystidia. E. Pileipellis elements. Scale bars are 10 μm for all. 76 Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107

Fig. 11. Pluteus aurantiorugosus (Trog) Sacc. A. Basidiospores, MG Weaver 6-29-63-N1. B. Basidium, MG Weaver 6-29-63-N1. C.–E. Pleurocystidia. C. MG Weaver 6-29-63-N1. D. R Kerrigan 1052 E. F Hoseny 1740. F. Cheilocystidia, MG Weaver 6-29-63-N1. G. Pileipellis elements, MG Weaver 6-29-63- N1. Scale bars are 10 μm for all. Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 77

Fig. 12. Pluteus californicus McClatchie. All illustrations McClatchie 1323 (designated lectotype). A. Basidiospores. B. Basidia. C. Pleurocystidia. D. Cheilocystidia. E. Pileipellis elements. Scale bars are 10 μm for all. 78 Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107

Fig. 13. Pluteus chrysophlebius (Berk. & Ravenel) Sacc. var. chrysophlebius. Basidiocarps of Minnis 3- 09-20-5. Photograph by Walter Sundberg. Scale bar is approximately 5 mm. Note: Stipes are yellowish. Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 79

Fig. 14. Type illustration by C.H. Peck of Agaricus admirabilis Peck: “123, Ag. (Pluteus) admirabilis n. sp., on old logs in woods, Gregg, Sept.” (NYS illustration-I-3001)—designated lectotype. Copyright: New York State Museum, Albany, NY. 80 Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107

Fig. 15. Pluteus chrysophlebius (Berk. & Ravenel) Sacc. var. chrysophlebius. All illustrations HW Ravenel, s.n. (lectotype of Agaricus chrysophlebius Berk. & Ravenel). A. Basidiospores. B. Basidia. C. Pleurocystidia. D. Cheilocystidia. E. Pileipellis elements. Scale bars are 10 μm for all. Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 81

Fig. 16. Pluteus chrysophlebius (Berk. & Ravenel) Sacc. var. chrysophlebius. All illustrations FS Earle 1664 (holotype of Pluteus aurantiacus Murrill). A. Basidiospores. B. Basidia. C. Pleurocystidia. D. Cheilocystidium. E. Pileipellis elements. Scale bars are 10 μm for all. 82 Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107

Fig. 17. Pluteus chrysophlebius (Berk. & Ravenel) Sacc. var. chrysophlebius. All illustrations WA Murrill 840 (holotype of Pluteus melleus Murrill). A. Basidiospores. B. Basidia. C. Pleurocystidia. D. Cheilocystidia. E. Pileipellis elements. Scale bars are 10 μm for all. Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 83

Fig. 18. Pluteus chrysophlebius (Berk. & Ravenel) Sacc. var. chrysophlebius. All illustrations WA Murrill and EL Murrill 206 (original collection of Pluteus melleus Murrill). A. Basidiospores. B. Basidia. C. Pleurocystidia. D. Cheilocystidia. E. Pileipellis elements. Scale bars are 10 μm for all. 84 Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107

Fig. 19. Pluteus chrysophlebius (Berk. & Ravenel) Sacc. var. chrysophlebius. All illustrations Minnis SB2003. A. Basidiospores. B. Basidia. C. Pleurocystidia. D. Cheilocystidia. E. Pileipellis elements. Scale bars are 10 μm for all. Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 85

Fig. 20. Pluteus chrysophlebius (Berk. & Ravenel) Sacc. var. chrysophlebius. A.–B. Basidiospores. A. HD Thiers 18841. B. RL Homola 1352. C.–D. Basidia. C. HD Thiers 18841. D. RL Homola 1352. E.–G. Pleurocystidia. E. HD Thiers 18841. F. RL Homola 1352. G. RL Homola 109. H.–I. Cheilocystidia. H. HD Thiers 18841. I. RL Homola 1352. J.–K. Pileipellis elements. J. HD Thiers 18841 . K. RL Homola 1352. Scale bars are 10 μm for all. 86 Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107

Fig. 21. Pluteus cyanopus Quél. All illustrations MG Weaver 1430. A. Basidiospores. B. Basidia. C. Pleurocystidia. D. Cheilocystidia. E. Pileipellis elements. Scale bars are 10 μm for all. Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 87

Fig. 22. Pluteus deceptivus Minnis & Sundb. All illustrations AH Smith 18670 (holotype of Pluteus deceptivus). A. Basidiospores. B. Basidia. C. Pleurocystidia. D. Cheilocystidia. E. Pileipellis elements. Scale bars are 10 μm for all. 88 Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107

Fig. 23. Pluteus fulvibadius Murrill. Basidiocarp of Minnis 6-09-09-1. Photograph provided by courtesy of Leon Shernoff. Scale bar is approximately 1 cm. Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 89

Fig. 24. Pluteus fulvibadius Murrill. All illustrations WA Murrill 760 (holotype). A. Basidiospores. B. Basidia and basidiole. C. Pleurocystidia. D. Cheilocystidia. E. Pileipellis elements. Scale bars are 10 μm for all. 90 Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107

Fig. 25. Pluteus fulvibadius Murrill. All illustrations FS Earle 1589 (holotype of Pluteus melleipes Murrill). A. Basidiospores. B. Basidium. C. Pleurocystidia. D. Cheilocystidia. E. Pileipellis elements. Scale bars are 10 μm for all. Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 91

Fig. 26. Pluteus fulvibadius Murrill. All illustrations Minnis 6-9-23-3. A. Basidiospores. B. Basidium. C. Pleurocystidia. D. Cheilocystidia. E. Pileipellis elements. Scale bars are 10 μm for all. 92 Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107

Fig. 27. Pluteus homolae Minnis & Sundb. All illustrations FS Earle 132 (holotype of Prunulus ludovicianus Murrill). A. Basidiospores. B. Basidia. C. Pleurocystidia. D. Cheilocystidia. E. Pileipellis elements. Scale bars are 10 μm for all. Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 93

Fig. 28. Pluteus jamaicensis Murrill. All illustrations Murrill F 18713 (isotype of Pluteus alachuanus Murrill). A. Basidiospores. B. Basidia. C. Pleurocystidia. D. Cheilocystidia. E. Pileipellis elements. Scale bars are 10 μm for all. 94 Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107

Fig. 29. Pluteus jamaicensis Murrill. All illustrations Singer F 1107 (holotype of Pluteus venosus Singer). A. Basidiospores. B. Basidium. C. Pleurocystidia. D. Cheilocystidia. E. Pileipellis elements. Scale bars are 10 μm for all. Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 95

Fig. 30. Pluteus ludovicianus Murrill. All illustrations FS Earle 130 (holotype). A. Basidiospores. B. Basidia. C. Pleurocystidia. D. Cheilocystidia. E. Pileipellis elements. Scale bars are 10 μm for all. 96 Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107

Fig. 31. Pluteus pallidus Homola. A.–B. Basidiospores. A. Smith 62487 (paratype). B. Shaffer 2633 (paratype). C.–D. Basidia. C. Smith 62487. D. Shaffer 2633. E.–F. Pleurocystidia. E. Smith 62487. F. Shaffer 2633. G. Cheilocystidia, Smith 62487. H.–I. Pileipellis elements. H. Smith 62487. I. Shaffer 2633. Scale bars are 10 μm for all. Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 97

Fig. 32. Pluteus phaeocyanopus Minnis & Sundb. All illustrations HD Thiers 18076 (holotype). A. Basidiospores. B. Basidia. C. Pleurocystidia. D. Cheilocystidia. E. Pileipellis elements. Scale bars are 10 μm for all. 98 Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107

Fig. 33. Pluteus phlebophorus (Ditmar : Fr.) P. Kumm. Basidiocarps of Minnis 7-09-14-1. Photograph by Joe McFarland. Scale bar is approximately 1 cm. Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 99

Fig. 34. Pluteus phlebophorus (Ditmar : Fr.) P. Kumm. All illustrations CH Peck, s.n. (designated lectotype of Pluteus admirabilis var. fuscus Peck). A. Basidiospores. B. Basidia. C. Pleurocystidia. D. Cheilocystidia. E. Pileipellis elements. Scale bars are 10 μm for all. 100 Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107

Fig. 35. Pluteus phlebophorus (Ditmar : Fr.) P. Kumm. A. Basidiospores, RL Homola 1849. B. Basidia, RL Homola 1849. C.–E. Pleurocystidia. C. RL Homola 1849. D. RL Shaffer 4226. E. C5584. F.–H. Cheilocystidia. F. RL Homola 1849. G. RL Shaffer 4226. H C5584. I.–K. Pileipellis elements. I. RL Homola 1849. J. RL Shaffer 4226. K. C5584. Scale bars are 10 μm for all. Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 101

Fig. 36. Pluteus praerugosus Murrill. All illustrations WA Murrill, s.n. (holotype). A. Basidiospores. B. Basidia. C. Pleurocystidia. D. Cheilocystidia. E. Pileipellis elements. Scale bars are 10 μm for all. 102 Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107

Fig. 37. Pluteus pulverulentus var. pseudonanus Singer. All illustrations F 885 (paratype). A. Basidiospores. B. Basidia. C. Pleurocystidia. D. Cheilocystidia. E. Pileipellis elements. Scale bars are 10 μm for all. Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 103

Fig. 38. Pluteus roseocandidus G.F. Atk. All illustrations 18384 (holotype). A. Basidiospores. B. Basidia. C. Pleurocystidia. D. Cheilocystidia. E. Pileipellis elements. Scale bars are 10 μm for all. 104 Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107

Fig. 39. Pluteus podospileus Sacc. & Cub. All illustrations C5647. A. Basidiospores. B. Basidium. C. Pleurocystidia. Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 105

Fig. 40. Pluteus romellii (Britzelm.) Lapl. A. Basidiospores, RL Shaffer 7010. B. Basidium, RL Shaffer 7010. C.–D. Pleurocystidia. C. RL Shaffer 7010. D. RL Shaffer 4525. E. Cheilocystidia, RL Shaffer 7010. F. Pileipellis elements, RL Shaffer 7010. Scale bars are 10 μm for all. 106 Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107

Fig. 41. Pluteus campanulatus Murrill. All illustrations LM Underwood and FS Earle 655 (holotype). A. Basidiospores. B. Pileipellis elements. Scale bars are 10 μm for all.

Fig. 42. Icon. Pluteus tortus. From the Curtis Gates Lloyd Papers, Collection 11, Box 59, Volume 44. Courtesy of the Lloyd Library and Museum, Cincinnati, Ohio.—designated lectotype. Minnis & Sundberg. Pluteus section Celluloderma in the U.S.A. North American Fungi 5(1):1-107 107

Fig. 43. Pluteus umbrinidiscus Murrill. All illustrations WA Murrill and EL Murrill, s.n. (holotype). A. Basidiospores. B. Basidium. C. Pleurocystidia. D. Pileipellis elements. Scale bars are 10 μm for all.