SYSTEMATICS OF BOLETACEAE FROM THE GUIANA SHIELD
by
Tara Diva Fulgenzi
A Thesis Presented to The Faculty of Humboldt State University
In Partial Fulfillment Of the Requirements for the Degree Master of Arts In Biological Sciences
May 2009
SYSTEMATICS OF BOLETACEAE FROM THE GUIANA SHIELD
by
Tara Diva Fulgenzi
We certify that we have read this study and that it conforms to acceptable standards of scholarly presentation and is fully acceptable, in scope and quality, as a thesis for the degree of Master of Arts.
Dr. Terry Henkel, Major Professor Date
Dr. Mihai Tomescu, Committee Member Date
Dr. Brian Arbogast, Committee Member Date
Dr. Michael Mesler, Graduate Coordinator, Committee Member Date
Chris A. Hopper, Interim Graduate Dean Date
ABSTRACT
SYSTEMATICS OF BOLETACEAE FROM THE GUIANA SHIELD
Tara Diva Fulgenzi
This work is a taxonomic study of nine species in the ectomycorrhizal fungal
family Boletaceae (Basidiomycota) from Neotropical rainforests of Guyana, in
northeastern South America. Morphospecies collections from the following genera were
studied: Tylopilus, Boletellus, Austroboletus, and Fistulinella. Of these taxa, five were
deemed to be new species and were given complete descriptions, distributions, visual
documentation of salient features, and accompanying holotype collections. The
remaining four taxa were deemed to have been previously described and were thus given
new distribution records, and accompanying taxonomic descriptions which highlighted
salient features that differed in the material studied from the material previously
described. New taxa include Tylopilus orsonianus, Boletellus exiguus, Boletellus
dicymbophilus, Boletellus piakaii, and Fistulinella cinereoalba. New distribution records were given to Tylopilus eximius, Boletellus ananas var. ananas, Austroboletus rostrupii, and Austroboletus festivus.
iii
ACKNOWLEDGEMENTS
This research was made possible by grants made to Dr. Terry Henkel from the
National Geographic Society’s Committee for Research and Exploration, the Smithsonian
Insitution’s Biological Diversity of the Guianas Program, the Linnaean Society of
London, the Duke University Department of Botany, and the Humboldt State University
Foundation. Grants provided by the Sonoma County Mycological Association and the
Greg Jennings Award also facilitated this research. Field assistance in Guyana was
provided by Mimi Chin, Cathie Aime, Christopher Andrew, Leonard Williams, Valentino
Joseph, Francino Edmond, and Luciano Edmond. Research permits were granted by the
Guyana Environment Protection Agency. The author would like to thank Dr. Terry W.
Henkel for his excellent advising, and for providing extremely useful editorial comments
on resulting manuscripts, insights, support, and camaraderie in the field and office. Dr.
Roy E. Halling provided invaluable help, insights, and support throughout this project.
Jordan R. Mayor provided line drawings in the Boletellus chapter. Christian Feuillet
provided the Latin translation for Boletellus piakaii. Nomenclatural clarifications from
Scott Redhead are greatly appreciated. Excellent critical reviews were provided by
boletologists Beatriz Ortiz-Santana and Timothy Baroni. Shaun Pennycook provided
valuable nomenclatural advice. The members of the Sonoma County Mycological
Society are thanked for financial support. The following professors at Humboldt State
University, Leslie Vandermolen, Dr. Mark Wilson, and Dr. Bruce O’Gara provided invaluable support throughout my college career. My committee members Dr. Michael
iv
Mesler, Dr. Mihai Tomescu, and Dr. Brian Arbogast are thanked for their support and involvement in this project. My family and friends are thanked for their love, support, and companionship along the way. Lastly I would like to recognize the beautiful country of Guyana for still providing the world with new wonders, and to the countrysides of
Humboldt County and Oahu for providing much needed solace.
v
TABLE OF CONTENTS
ABSTRACT...... iii
ACKNOWLEDGEMENTS...... iv
TABLE OF CONTENTS...... vi
LIST OF FIGURES ...... vii
INTRODUCTION ...... 1
CHAPTER 1 TYLOPILUS ORSONIANUS SP. NOV. AND TYLOPILUS EXIMIUS FROM GUYANA...... 6
CHAPTER 2 NEW SPECIES OF BOLETELLUS AND A NEW DISTRIBUTION RECORD FOR BOLETELLUS ANANAS VAR. ANANAS...... 22
CHAPTER 3 FISTULINELLA CINEREOALBA SP. NOV AND NEW DISTRIBUION RECORDS FOR AUSTROBOLETUS FROM GUYANA...... 53
LITERATURE CITED ...... 75
vi
LIST OF FIGURES
Figure Page
1. Basidiomata of Tylopilus orsonianus (HOLOTYPE; Henkel 8106), × 0.7...... 12
2. Microscopic features of Tylopilus orsonianus (HOLOTYPE; Henkel 8106) a. Basidia. b. Basidiospores. c. Cystidia. Bar = 10 μm...... 12
3. Basidiomata of Tylopilus eximius. a. Immature basidioma (Henkel 7433), × 1.5. b. Mature basidioma showing hymenophore (Henkel 8059), × 1...... 18
4. Microscopic features of Tylopilus eximius (Henkel 8059). a. Basidia. b.Basidiospores. c. Cystidia. Bar = 10 μm...... 19
5. Basidiomata of Boletellus exiguus (HOLOTYPE; Henkel 8696). Bar = 10 mm...... 29
6. Microscopic features of Boletellus exiguus (HOLOTYPE; Henkel 8696) a. Basidia. b. Pleurocystidia, in Melzer’s. c. Basidiospores. Bar = 10 µm...... 29
7. Basidiomata of Boletellus dicymbophilus (Henkel 8818). Bar = 10 mm...... 35
8. Microscopic features of Boletellus dicymbophilus (HOLOTYPE; Henkel 8616) a. Basidia. b. Pleurocystidia. c. Basidiospores. Bar = 10 µm...... 35
9. Basidioma of Boletellus piakaii (HOLOTYPE; Henkel 8728). a. Dorsal. b. Ventral. Bar = 10 mm...... 41
10. Microscopic features of Boletellus piakaii (HOLOTYPE; Henkel 8728) a. Basidia. b. Pleurocystidia. c. Basidiospores. Bar = 10 µm...... 41
11. Basidiomata of Boletellus ananas var. ananas. a. Henkel 8819. b. Fruiting habit on humic deposit of Dicymbe trunk, Upper Potaro Basin, Guyana. Bar = 10 mm... 48
12. Microscopic features of Boletellus ananas var. ananas (Henkel 8168) a. Basidia. b. Pleurocystidia. c. Basidiospores. Bar = 10 µm...... 48
13. Scanning electron micrographs of basidiospores of Boletellus species from Guyana. a. Boletellus exiguus (HOLOTYPE; Henkel 8696), ×6700. b. Boletellusexiguus (Henkel 8809), ×8900. c. Boletellus dicymbophilus (Henkel 8824), ×3200. Bar = 1 µm...... 52
14. Scanning electron micrographs of basidiospores of Boletellus species from Guyana. a. Boletellus piakaii (Henkel 8013) ×4000. b. Boletellus ananas var. ananas (Henkel 8168) ×6300...... 52
vii
15. Basidiomata of Fistulinella cinereoalba. a. HOLOTYPE (Henkel 8471). b. Field habit, Upper Potaro Basin, Guyana. Bar = 10 mm...... 60
16. Microscopic features of Fistulinella cinereoalba (HOLOTYPE; Henkel 8471) a. Basidia. b. Pleurocystidia. c. Basidiospores. d. Cheilocystidia. Bar = 10 µm..... 60
17. Basidiomata of Austroboletus rostrupii. a. Henkel 8189. b. Field habit, Upper Ireng Basin, Guyana. Bar = 10 mm...... 66
18. Microscopic features of Austroboletus rostrupii (Henkel 8189) a. Basidia. b Basidiospores. c. Pleurocystidia. Bar = 10 µm...... 66
19. Basidiomata of Austroboletus festivus. a. Henkel 8164. b. Mature specimen, Upper Potaro Basin, Guyana. Bar = 10 mm...... 72
20. Microscopic features of Austroboletus festivus (Henkel 8164) a. Basidia. b. Pleurocystidia. c. Basidiospores. d. Cheilocystidia. Bar = 10 µm...... 72
21. Scanning electron micrographs of basidiospores. a. Austroboletus rostrupii (Henkel 8189). b. Fistulinella cinereoalba (HOLOTYPE; Henkel 8471). c. Austroboletus festivus (Henkel 8164). Bar = 1 µm...... 74
viii
INTRODUCTION
Fungal diversity, function, and the importance of taxonomy. It is estimated that there are 1.2−1.5 million species of fungi worldwide, yet less than 75,000 species (5 %) have been described (Hawksworth 2001). The majority of the world’s unknown fungal diversity lies within twenty degrees north and twenty degrees south; i.e. the tropics
(Hawksworth 2001; Watling et al 2002). Fungi are integral parts of ecosystems in which they are found, e.g. in nutrient cycling, decomposition, and formation of symbioses.
They are therefore of utmost importance in floristic and ecological studies (Watling et al
2002). When conducting floristic and ecological surveys, individual species are encountered that are integral parts of that particular community. Thus placing a name that is accompanied by a detailed description and type collection behind the individuals that we encounter in nature contributes fundamentally to floristic and ecological studies of fungi, and those plants and animal species with which they interact.
Ectomycorrhizal fungi in the tropics. Mycorrhizal symbioses between plants and fungi are ubiquitous in terrestrial ecosystems (Trappe 1977; Halling 2001). Roughly
5000 described species of macrofungi are obligately ectomycorrhizal (Hawksworth et al
1995). The host trees provide carbon to the fungus as well as a relatively competition- free environment. In turn, the fungus provides water and mineral uptake superior to that which the tree roots could do alone, or in association with arbuscular mycorrhizal (AM)
1 2 fungi (Tarkka et al 2005). Ectomycorrhizal fungi are associated with a narrow range of woody vascular plant families, which primarily occur in the temperate and boreal regions
(e.g. Fagaceae, Pinaceae), where the ectomycorrhizal syndrome has been heavily documented (Halling 2001). In the past, tropical rainforests have been thought to be largely devoid of ectomycorrhizal fungi because of the absence of their host trees. It is now widely accepted that although the majority of tropical tree species form AM, ectomycorrhizal trees are a conspicuous component of the tropical rainforests in specific regions (Alexander 1989). Tropical trees that form ectomycorrhizae are primarily in the
Dipterocarpaceae (Southeast Asia) and Fabaceae subfamily Caesalpinioideae (tropical
Africa, and parts of tropical South America), in these locations they often form monodominant stands (Corner 1972; Singer et al 1983; Alexander 1989; Watling & Lee
1995; Henkel et al 2002). One could not adequately study these unique tropical systems of monodominant stands without looking at the ectomycorrhizal fungi involved. These symbiotic fungi may be a key component allowing for host tree dominance, in an otherwise tree-species rich area (Alexander 1989; Newbery et al 1997; Henkel 2003).
Ectomycorrhizal fungi in Guyana. In the Pakaraima Mountains of Guyana, in northeastern South America, there are large upland expanses with high diversity mixed species rainforest, juxtaposed with monodominant Dicymbe corymbosa Spruce ex Benth. forests (Henkel 2003; Henkel et al 2002; Henkel et al 2005). Dicymbe corymbosa is a member of the Fabaceae subfamily Caesalpinioideae, tribe Amherstieae, and has been shown to be ectomycorrhizal, as are other members of this tribe in West Africa
(Alexander 1989; Henkel et al 2002). One component of current research on the
3 Dicymbe system in Guyana is a multi-year study looking at macrofungal diversity in the
D. corymbosa stands, and the surrounding AM mixed forests, and comparing fungal guilds and their ecological significance in these highly contrasting forest types (Henkel unpubl. data). Many of the fungi encountered in both the monodominant and mixed stands are undescribed species. Currently >150 morphospecies of ectomycorrhizal fungi have been collected in the Dicymbe forests, effectively doubling the number of ectomycorrhizal fungi known from the lowland Neotropics. Traditional taxonomic work is needed on these fungi to facilitate ongoing ecological research in Guyana, and expand knowledge of tropical macrofungal diversity overall. For those groups already studied,
>70 % are new taxa at the specific or generic level (Henkel 1999; Henkel 2001; Henkel et al 2000; Henkel et al 2004; Miller et al 2001; Miller et al 2002; Simmons et al 2001;
Aime et al 2003; Matheny et al 2003; Thacker & Henkel 2004).
Overview of research. I carried out a comprehensive taxonomic study of the ectomycorrhizal fungal family Boletaceae (i.e. the "boletes", agaricoid mushrooms with a tubular hymenophore; Snell & Dick 1970; Smith & Thiers 1971; Bessette et al 2000).
Most distribution records for these fungi are from North America, Eurasia, and Southeast
Asia (Bessette et al 2000; Binder & Bresinsky 2002), and to a lesser extent from tropical
Africa, with few records from tropical South America (Singer et al 1983). The boletes are especially rich at the Guyana site, numbering at least 20 morphospecies in numerous genera (Tylopilus, Xerocomus, Austroboletus, Pulveroboletus, Boletellus, and
Fistulinella) from a single local collecting area in the Upper Potaro River Basin. I have completed the descriptions and new distribution records for all of the taxa in the
4 following genera: Tylopilus (1 sp. nov., 1 new distribution), Boletellus (3 sp. nov, 1 new distribution), Austroboletus (2 new distributions), and Fistulinella (1 sp. nov.).
Significance of research. From an alpha-taxonomic standpoint, this research has bearing on mycology as a whole. The study of tropical boletes has revealed that current morphological concepts of bolete genera, which are based on temperate taxa, are incomplete, because many tropical collections have characteristics of more than one genus as understood by temperate mycologists (i.e. they bridge accepted “generic boundaries”; e.g Corner 1972; 1974; Henkel 1999). Only by documenting the tropical bolete mycota will we gain a complete understanding of the systematic relationships within this important group of macrofungi (Corner 1972). The rich assemblage of
Boletaceae at the Guyana site, several of which have already been shown to bridge accepted generic and infrageneric boundaries, provides a good framework for expanding taxonomic concepts and will ultimately contribute to revisions of the various genera
(Henkel 1999; Fulgenzi et al 2009).
Molecular systematic studies have demonstrated a well supported Boletales clade that is sister to the Euagarics (gilled-mushrooms) clade, and have shown consistent strong support for a boletoid radiation and a suilloid radiation (families Boletaceae and
Suillaceae) within the Boletales clade (Order Boletales; Kretzer & Bruns 1999; Grubisha et al 2001; Binder & Hibbett 2002; Binder & Bresinsky 2002). However the primary molecular literature lacks consensus on support (or lack thereof) within the boletoid clade for bolete genera as currently defined. Many of the morphologically defined bolete genera appear to be polyphyletic (Jarosch & Besl 2001; Grubisha et al 2001; Hibbett &
5 Binder unpubl. data). By describing and documenting the bolete mycota of an understudied region of the tropics, where unusual macromorphologies have been found, I provide material that will facilitate a more coherent understanding of the contemporary systematics of the Boletales.
CHAPTER 1
TYLOPILUS ORSONIANUS SP. NOV. AND TYLOPILUS EXIMIUS FROM GUYANA
Abstract: Tylopilus orsonianus sp. nov. and Tylopilus eximius (Boletaceae,
Basidiomycota) are described for the first time from the Pakaraima Mountains of
Guyana. Both boletes occur in forests dominated by ectomycorrhizal trees in the genus
Dicymbe (Caesalpiniaceae). A key to Tylopilus species distinguishes those known to
occur in Guyana.
Key words: Boletaceae, Caesalpiniaceae, ectomycorrhizae, Guiana Shield,
neotropics, taxonomy
Introduction
Species of Boletaceae (Basidiomycota) are prominent components of the
ectomycorrhizal macromycota associated with the leguminous genus Dicymbe (Fabaceae
subfam. Caesalpinioideae, tribe Amherstieae) in the Pakaraima Mountains of Guyana
(Henkel et al. 2002). This paper completes the taxonomic descriptions of Tylopilus P.
Karst. currently known from Guyana (Henkel 1999; 2001). Ninety six species of
Tylopilus are currently known worldwide, with over half described from either the paleo-
or neotropics (Heinemann & Goossens-Fontana 1954; Singer et al. 1983, 1991; Halling
& Mueller 2001). We describe here a new species, Tylopilus orsonianus, and note a new
6
7 distribution record for Tylopilus eximius (Pk.) Singer. A key to Tylopilus species known in Guyana is provided.
Materials and Methods
Collections were made during the May–July rainy seasons of 2000–2005 from the Upper
Potaro River Basin, within a 5 km radius of a permanent base camp at 5° 18' 04.8" N; 59°
54' 40.4" W; elevation 710 m. The site is located in an undulating valley approximately
20 km east of Mt. Ayanganna (2200 m), and is densely forested with a mosaic of primary
Dicymbe-dominated and mixed forests of the Eschweilera-Licania association (Fanshawe
1952, further site details: Henkel 2003). An additional collection of Tylopilus orsonianus was made in the Upper Ireng River Basin, approximately 30 km south of the Potaro site.
All collections were made in forests dominated by Dicymbe corymbosa Spruce ex Benth.
Macroscopic features were described from fresh basidiomata in the field. Colors were described subjectively and coded according to Kornerup and Wanscher (1978), with color plates noted in parentheses (e.g., 3C4). Macrochemical tests were performed according to the methods of Singer (1986). Fungi were dried with silica gel (Miller et al. 2002).
Micromorphological features of dried specimens were examined with an Olympus
BX51 microscope equipped with bright field and phase contrast optics. Fungal tissue
was rehydrated and mounted in either H20, 3% KOH, or Melzer's solution. A minimum
of 20 basidiospores, basidia, cystidia and other structures were measured for each
collection examined. Line drawings were traced from digital photographs. Specimens
are deposited in the following herbaria: BRG; HSU; and NY (Holmgren et al. 1990).
8
Taxonomy
Tylopilus orsonianus Fulgenzi and T.W. Henkel, sp. nov.
Latin diagnosis: T. rubrobrunneus et T. indecisus affinis, a qua differt colore pilei, forma stipitis et proprietatibus superficiei, magnitudinibus sporarum basidiorum et cystidiorum, et in KOH colore et textura mediostrati hymenophori.
HOLOTYPE: Henkel 8106 (BRG; ISOTYPE: HSU, NY)
Pileus 26−66 (98) mm broad, convex to planoconvex, brown throughout
(6E6−7F6) to tannish brown (4B4−4B7) with age, velutinous, becoming minutely areolate when mature (under lens), dry, margin slightly inrolled and entire; trama 1−3 mm thick at margin, 4−10 mm over tubes, 5−17 mm above stipe, white to cream (3A3) to light greyish yellow (3B3), unchanging, solid. Odor fragrant; taste mild, nutty (not bitter). Tubes 1−3 mm long at margin, 3−9 mm centrally, 1−4 mm at stipe, narrowly and deeply depressed around stipe, cream yellow (3A4) to light yellow (3B4−4B4), slowly and slightly browning with exposure; tube mouths cream yellow (3A3−3A4) to greyish yellow (4B3), browning slightly with pressure; pores 1−2 per mm, isodiametric to subovate. Stipe 48−111 (140) mm × 11−34 (42) mm centrally, 6.5−22 (30) mm at apex,
6−23 mm at base, subequal, tapering gradually upward, strongly attenuated at extreme base, occasionally curving, olivaceous brown throughout (5E6) to dark brown
(6F5−6F8); extreme apex light greyish yellow (3B4) to light greyish orange (4B5), smooth, finely pubescent under lens, coarsely reticulate over upper 1/3−2/3; reticulum less pronounced towards base, lower 1/4 with a low, densely matted dark greyish brown
9 tomentum (5E4−5E5); extreme base with white to cream mycelium, occasionally subtended by greyish brown rhizomorphs and brown ectomycorrhizae; trama cream in upper 3/4, lower 1/4 olivaceous brown (4E4) to dark brown (5F6), discoloring throughout along larval tunnels (5F6), otherwise unchanging, solid, less so with age.
Basidiospores flesh pink (6B2−6C2−6C3) in light to medium deposit, 11−14.5
μm × 4.9−7.4 μm (mean Q = 2.31), ellipsoid to subfusiform, faint pink in H2O, hyaline in
KOH, inamyloid, 1−2 guttulate; hilar appendage 0.4−0.8 μm long; wall 0.5−0.9 μm thick,
smooth. Basidia 24.7−41.3 μm × 9.6−16.9 μm, clavate, thin walled, hyaline in H2O and
KOH, 4-sterigmate. Hymenial cystidia 39.5−71.6 μm × 5.7−12.4 μm, ventricose to ventricose-rostrate, occasionally more cylindrical, frequent, arising from the subhymenium, projecting 17−40 μm above the hymenial palisade, hyaline, devoid of refractive contents. Hymenophoral trama boletoid; mediostratum 24.7−44.5 μm wide, of many narrow parallel hyphae, these yellow orange in H2O, gelatinized and light yellow
orange in KOH, lateral stratum hyphae 4.0−5.7 μm wide, hyaline, nongelatinized,
strongly divergent. Pileipellis an interwoven trichodermial palisade of cylindrical
elements with inflated terminal cells, in mass light golden brown in H2O, lighter in KOH;
terminal cells 15.3−49.4 μm × 7.4−12.4 μm wide, faint golden brown in H2O, hyaline in
KOH, inamyloid, cylindrical to mucronate to ventricose-rostrate, occasionally globose to
clavate. Pileus trama interwoven; individual hyphae 4−5 μm wide, thin walled, light
golden in H2O, hyaline in KOH, regularly septate. Stipitipellis a highly interwoven trichodermial palisade, dark brown in mass in KOH; individual hyphae 6.3−9.4 μm wide;
10 terminal cells golden brown in H2O, lighter in KOH, thin walled, clavate to cylindrical,
occasionally broadly mucronate; subpellis hyphae with spirally arranged, yellowish
encrusting pigments; upper stipe reticulum with infrequent basidia. Clamp connections
absent. Macrochemical reactions: NH4OH negative on pileus surface, burgundy to black
on trama of stipe base; KOH yellowing on pileus surface, burgundy to black on trama of
stipe base.
Habitat, habit, and distribution. Solitary to scattered on root mat in forests
dominated by Dicymbe corymbosa; known from the type locality in the Upper Potaro
Basin and adjacent Upper Ireng Basin of Guyana.
Etymology. This species epithet honors the late agaricologist Dr. Orson K. Miller
Jr.
Specimens examined. GUYANA. REGION 8 POTARO-SIPARUNI: Pakaraima
Mountains, Upper Ireng River, 1 km downstream from Kurutuik Falls, 7 Jan 1998,
Henkel 6286 (BRG; HSU); Upper Potaro River, 5o 18′ 04.8″ N, 59o 54′ 40.4″ W,
elevation 710 m, vicinity of Potaro base camp, 19 May 2000, Henkel 7407 (BRG; HSU);
vicinity of Potaro base camp, 26 May 2000, Henkel 7428 (BRG; HSU); vicinity of Potaro
base camp, 23 June 2000, Henkel 7541 (BRG; HSU); vicinity of Potaro base camp, 23
June 2000, Henkel 7548 (BRG; HSU); vicinity of Potaro base camp, 13 July 2000,
Henkel 7571 (BRG; HSU); vicinity of Potaro base camp, 18 July 2000, Henkel 7637
(BRG; HSU); 3.5 km east of Potaro base camp, 11 May 2001, Henkel 8085 (BRG; HSU);
4 km southwest of Potaro base camp near Dicymbe plot 3, 12 May 2001, Henkel 8106
(HOLOTYPE, BRG; ISOTYPE: HSU, NY); 4 km southwest of Potaro base camp near
11
Dicymbe plot 3, 18 May 2001, Henkel 8169 (BRG; HSU); vicinity of Potaro base camp,
29 June 2001, Henkel 8421 (BRG; HSU); vicinity of Potaro base camp, 22 May 2002,
Henkel 8480 (BRG; HSU); 1 km west of Potaro base camp, 30 May 2005, Henkel 8814
(BRG; HSU); 0.75 km west of Potaro base camp, 3 June 2005, Henkel 8830 (BRG;
HSU); 0.3 km southeast of Potaro base camp on Dicymbe masting plot 5, 4 June 2005,
Henkel 8834 (BRG; HSU); 2 km southeast of Potaro base camp on Benny’s ridge on LP1
Dicymbe plot, 5 June 2005, Henkel 8837 (BRG; HSU); vicinity of Potaro base camp, 6
June 2005, Henkel 8845 (BRG; HSU).
12
Figure 1. Basidiomata of Tylopilus orsonianus (HOLOTYPE; Henkel 8106), × 0.7.
Figure 2. Microscopic features of Tylopilus orsonianus (HOLOTYPE; Henkel 8106) a. Basidia. b. Basidiospores. c. Cystidia. Bar = 10 μm.
13
Commentary. Tylopilus orsonianus is a distinctive bolete recognized in the field by the velutinous brown to tan brown pileus, robust subequal brown stipe with coarse reticulations over the upper portion, and cream yellow hymenophore. Microscopically T. orsonianus is distinguished by elongated spores, abundant ventricose-rostrate hymenial cystidia, a palisadic pileipellis of variously shaped hyphal elements, and a gelatinized yellow orange mediostratum in the tube trama as revived in KOH. This species fits the genus Tylopilus as commonly defined based on smooth spores with a nonolivaceous, flesh pink to pinkish brown deposit; within the genus it is best disposed in section
Tylopilus due to the lack of autoxidation in the trama, and the lack of a bluing reaction with NH4OH on the pileus (Smith & Thiers 1971, Singer 1986). Tylopilus orsonianus is
similar to the North American T. rubrobrunneus Mazzer & Smith (Mazzer & Smith
1967) but differs from T. rubrobrunneus in having a brown pileus that is lacking
vinaceous tones, a reticulate stipe that is strongly attenuated at the base, larger basidia
(24.7−41.3 μm × 9.6−16.9 μm vs. 20−26 μm × 8-11 μm), longer hymenial cystidia
(39.5−71.6 μm vs. 36−52 μm), wider spores (4.9−7.4 μm vs. 3−5 μm), a mediostratum
that is gelatinized and yellowish in KOH, and lacking a bitter taste (Smith & Thiers
1971). Tylopilus orsonianus is similar to the North American T. indecisus (Pk.) Murrill
(Smith & Thiers 1971) for features such as basidioma stature, mild taste, stipe
reticulation, a gelatinized hymenophoral mediostratum in KOH, and basidium shape, but
differs from T. indecisus in having a stipe that is strongly attenuated at the base, larger
basidia (24.7−41.3 μm × 9.6−16.9 μm vs.18−25 μm × 5−8 μm), more frequent hymenial
14 cystidia, wider spores (4.9−7.4 μm vs. 3−5 μm), and a yellow orange hymenophoral mediostratum in KOH (Smith & Thiers 1971). Tylopilus orsonianus is somewhat reminiscent of the montane neotropical Tylopilus bulbosus Halling & Mueller in basidioma stature, its non-bitter taste, and surface features of the pileus and stipe (Halling
& Mueller 2001). Tylopilus orsonianus differs from T. bulbosus in having wider spores
(4.9−7.4 μm vs. 4.2−4.9 μm), larger basidia (24.7−41.3 μm × 9.6−16.9 μm vs. 20−30 μm
× 8−12 μm), smaller hymenial cystidia (39.5−71.6 μm × 5.7−12.4 μm vs. 50−80 μm ×
8−14 μm), and a pileus, stipe, and hymenophore that consistently lack purple tones.
Additionally, the grayish rose tube mouths diagnostic for young T. bulbosus are lacking in T. orsonianus (Halling & Mueller 2001).
Tylopilus eximius (Pk.) Singer, Amer Midl Nat 37:109. 1947.
= Boletus robustus Frost non Fr., Bull Buffalo Soc Nat Sci 2:104. 1874.
≡ Boletus eximius Pk., J Mycol 3:54. 1887.
≡ Ceriomyces eximius (Pk.) Murrill, Mycologia 1:148. 1909.
≡ Leccinum eximium (Pk.) Singer, Persoonia 7:319. 1973.
Pileus 46−70 mm broad, convex to planoconvex, dark burgundy maroon throughout (10F5) to dark maroon (11F8−12F8) with age, densely velutinous, finely and irregularly rugulose throughout, dry, margin entire, extreme edge slightly inrolled; trama
1−2 mm thick at margin, 9−10 mm over tubes, 10−11 mm above stipe, off-white, unchanging, yellow around larval channels, solid. Odor mild; taste mild (not bitter).
15
Tubes 1−2 mm long at margin, 4−7 mm centrally, 10−11 mm at stipe, slightly and abruptly depressed around stipe, concolorous with tube mouths; tube mouths dull greyish lavender (9C3−10D6) to dark lavender pink (11E3−12E5) with age, quickly and moderately browning with pressure; pores 2−3 per mm, isodiametric. Stipe 52−84 mm ×
11−14 mm, equal to slightly tapering basally, more attenuated at extreme base, vinaceous grey (11E4−11D4) to maroon (9F5−10F5) throughout, with concolorous recurved subscabrous scales over upper 7/8, these occasionally darker maroon (10F6), lower 5−8 mm with dark magenta matted tomentum; extreme base with white strigose hairs; trama off-white, densely fibrous, discoloring light yellow slowly with exposure, very solid.
Basidiospores dull pinkish brown (7C5−7D5) in light to medium deposit, to chestnut brown (8E7) in heavy deposit, 9.7−12 μm × 4.2−5.3 μm (mean Q = 2.18), subfusiform, faint pink in H2O, lighter in KOH, inamyloid, 1−2 guttulate; hilar
appendage 0.2−0.7 μm long; wall 0.2−0.5 μm thick, smooth. Basidia 20.8−36.8 μm ×
7.4−14.6 μm, clavate to broadly clavate, thin walled, in immature hymenium hyaline in
H2O and KOH, in mature hymenium amber brown in H2O, lighter in KOH, 4-sterigmate;
contents granular. Hymenial cystidia 30.4−44.5 μm × 4.9−6.7 μm, sparsely distributed,
narrowly fusoid, occasionally more cylindrical, arising from the subhymenium,
projecting 8.2−20.3 μm above the hymenial palisade, hyaline, devoid of refractive
contents. Hymenophoral trama boletoid; mediostratum 19.8−34.6 μm wide, of many
narrow parallel hyphae, these golden yellow in H2O, lighter in KOH, lateral stratum
hyphae 3.5−5.8 μm wide, hyaline, regularly septate, strongly divergent. Pileipellis a
16 densely interwoven trichodermial palisade of cylindrical elements with inflated terminal cells, in mass golden brown in H2O, lighter in KOH; terminal cells 8.0−17.7 μm × 4.0−
6.0 μm, hyaline in H2O and KOH, inamyloid, cylindrical to clavate, occasionally mucronate, and rarely ventricose, encrusted with minute purple to bluish purple pigments,
these dissolving in KOH; subpellis interwoven with a few oleiferous hyphae. Pileus
trama densely interwoven; individual hyphae (4.5) 6.0−9.0 (11.9) μm wide, hyaline in
H2O and KOH, regularly septate, in mass golden brown in H2O, lighter in KOH.
Stipitipellis a densely interwoven trichodermial palisade of cylindrical elements with
inflated terminal cells, in mass dark golden brown in H2O, lighter in KOH; terminal cells
projecting 17.3−25.2 μm, clavate to mucronate, occasionally cylindrical to ventricose, more concentrated at scabrous regions, encrusted with minute purple to bluish purple
pigments, these dissolving in KOH; subpellis densely interwoven with a few oleiferous
hyphae. Stipe trama of densely packed parallel hyphae, 1.5−2.8 μm wide, hyaline in H2O
and KOH. Clamp connections absent. Macrochemical reactions: NH4OH on pileus
surface rapidly greenish purple, then blackening gradually, on pileus trama instantly dark
burgundy, slightly bluing the stipe scales, and darkening the stipitipellis; KOH bleaching the pileus surface, darkening the stipe surface.
Habitat, habit, and distribution. Solitary and rare on root mat in forests dominated by Dicymbe corymbosa in Guyana; also known from eastern North America,
Costa Rica, Japan, and Indonesia.
17
Specimens examined. GUYANA. REGION 8 POTARO-SIPARUNI. Pakaraima
Mountains, Upper Potaro River, 5o 18′ 04.8″ N, 59o 54′ 40.4″ W, elevation 710 m, 3 km upstream of Ayanganna airstrip and 1 km upstream from confluence with Whitewater creek, 2 June 2000, Henkel 7433 (BRG; HSU); 3.5 km east of Potaro base camp, 3 May
2001, Henkel 8017 (BRG; HSU); 3 km east of Potaro base camp, 7 May 2001, Henkel
8059 (BRG; HSU); 4 km southwest of Potaro base camp Dicymbe plot 3, 15 June 2002,
Henkel 8465 (BRG; HSU); vicinity of Potaro base camp, 7 June 2003, Henkel 8538
(BRG; HSU); 4 km southwest of Potaro base camp Dicymbe plot 3, 23 July 2003, Henkel
8600 (BRG; HSU; NY). USA. MAINE: Tylopilus eximius, 5 August 1979, Halling 2952
(NY). COSTA RICA. SAN JOSE: Tylopilus eximius, 1 July 1998, Halling 7798 (NY).
18
Figure 3. Basidiomata of Tylopilus eximius. a. Immature basidioma (Henkel 7433), × 1.5. b. Mature basidioma showing hymenophore (Henkel 8059), × 1.
19
Figure 4. Microscopic features of Tylopilus eximius (Henkel 8059). a. Basidia. b.Basidiospores. c. Cystidia. Bar = 10 μm.
Commentary. This is the first record for T. eximius from tropical South America.
The velutinous maroon pileus, lavender hymenophore, maroon stipe with recurved scales, and very solid trama are distinctive field characters, along with the rapid autoxidative reaction on the bruised hymenophore. These field characters are distinctive for, and consistent with, T. eximius as described from other regions (Peck 1887; Snell & Dick
1970; Hongo 1974; Halling & Mueller 2003). This species fits the genus Tylopilus as commonly defined based on smooth spores with a nonolivaceous, flesh pink to pinkish brown deposit, and is best disposed in section Oxydabiles due to the autoxidation of the context of the stipe, elongate spores with a pinkish brown print, and a non-bluing NH4OH reaction on the fresh exterior surfaces (Smith & Thiers 1971; Singer 1986). Guyana specimens deviate somewhat from T. eximius from other regions. The spores of the
Guyana material (9.7−12 μm) are similar in length to those from Costa Rica (10.5−13.3
μm; Halling & Mueller 2003), but are shorter than those from North America (11−17 (23)
μm; Snell & Dick 1970). The Guyana material also has decidedly denser trama, and cystidia that are much less frequent than either the Costa Rican or North American material. Tylopilus eximius appears to have wide host and geographical ranges, being originally described from Pinaceae and Fagaceae forests of the northeastern U.S.A. (Peck
1887) and subsequently recorded in association with Pinaceae in Eastern Canada (Snell &
Dick 1970), Fagaceae in Costa Rica (Halling & Mueller 2003), Pinaceae and Fagaceae in
20
Japan (Hongo 1974), Dipterocarpaceae in Indonesia (Halling, pers obs) and now with
Caesalpiniaceae in Guyana.
Key to Tylopilus in Guyana
1. Spores with a Q < 2…………………..…………………………………………….…..2
1. Spores with a Q > 2………………..……………………………………….…………..4
2. Spore deposit cream to golden yellow; NH4OH on pileus negative…T. ballouii
(Pk) Singer
2. Spore deposit flesh pink; NH4OH on pileus bright blue...... ……….…3
3. Pileus and tube mouths with lilac to violet tones; stipe with true reticulum on
apical portion; spores 8.2−10 μm × 5−5.9 μm; hymenial cystidia 27−40 μm × 7−
11μm…...... ……...... …………...T. pakaraimensis T. W. Henkel
3. Pileus and tube mouths lacking lilac to violet tones; stipe lacking true reticulum
but occasionally striate on basal portion; spores 9−12 μm × 4.8−6.4 μm; hymenial
cystidia 20−28 μm × 8−10 μm…....T. potamogeton var. irengensis (Singer) T. W.
Henkel
4. Hymenophore turning dark brown or black when bruised...... …...…………5
4. Hymenophore turning light brown when bruised……...... ………...……….7
5. Stipe with recurved scales; spore deposit dull pinkish brown…..T. eximius (Pk) Singer
5. Stipe lacking scales; spore deposit dark reddish brown or cinnamon brown…..…...…6
21
6. Basidiomata small; pileus 10−30 mm broad, velutinous to submatted, finely
areolate with age; spore deposit dark reddish brown; spores 10−13 (15) μm × 4−5
μm; hymenial cystidia 33−50 μm × 6−10 μm……………T. exiguus T. W. Henkel
6. Basidiomata larger; pileus 40−120 mm broad, squamulose; spore deposit
cinnamon brown, spores 12−15 μm × 3.6−4.8 μm; hymenial cystidia 25−33.8 μm
× 6.3−8.8 μm…………………………………...... T. rufonigricans T. W. Henkel
7. Stipe lacking reticulations, hollow and consistently curved; pileipellis a cutis; spores fusiform (mean Q = 2.96); hymenial cystidia 43−50 μm × 10−13 μm ....T. vinaceipallidus
(Corner) T. W. Henkel
7. Stipe reticulate, solid, irregularly curving to straight, pileipellis a trichodermial palisade; spores subfusiform (mean Q = 2.31); hymenial cystidia 39.5−71.6 μm × 5.7−
12.4 μm...... T. orsonianus Fulgenzi & T. W. Henkel
CHAPTER 2
NEW SPECIES OF BOLETELLUS AND A NEW DISTRIBUTION RECORD FOR BOLETELLUS ANANAS VAR. ANANAS
Abstract: Boletellus exiguus sp. nov., Boletellus dicymbophilus sp. nov., and
Boletellus piakaii sp. nov. (Boletaceae, Boletales, Basidiomycota) are described as new to science. Boletellus ananas var. ananas is recorded for the first time from the Guiana
Shield region. These boletes were collected from tropical forests dominated by ectomycorrhizal Dicymbe corymbosa (Caesalpiniaceae) in the Pakaraima Mountains of western Guyana.
Key Words: Boletaceae, Dicymbe, ectomycorrhizal fungi, Guiana Shield, neotropics
Introduction
The genus Boletellus Murrill (Boletaceae, Boletales, Basidiomycota) encompasses ~ 44 described species worldwide, the majority with tropical distributions
(Heinemann & Goossens-Fontana 1954; Snell & Dick 1970; Smith & Thiers 1971;
Corner 1972; Horak 1977; Singer 1986; Singer et al. 1992; Watling 2001; Halling &
Mueller 2005; Ortiz-Santana et al. 2007). Boletellus has been variably defined, yet all definitions have in common the following features: basidiospores that are olivaceous brown in deposit, a yellow hymenophore becoming olivaceous with time, and boletoid
(i.e. strongly divergent) tube trama. Despite these commonalities, individual author concepts vary. Singer (1986) adhered to a broad definition of Boletellus by including 22
23
species with longitudinally winged or ridged spores (sections Boletellus,
Chrysenteroidei, Ixocephali, and Dictyopodes), smooth spores (section Mirabilis), spores with imbedded short spines or pits (section Allospori), and reticulate spores (section
Retispori). Heinemann (1951) and Snell & Dick (1970) included species that have spores with imbedded short spines or pits (e.g. Boletellus purpurascens Heinem.), smooth spores
(e.g. Boletellus mirabilis (Murrill) Singer), as well as those with longitudinally striate spores. Smith & Thiers (1971) argued against Singer's broad concept of the genus and included only species with spores that are longitudinally winged, ridged, or striate; by doing so, Boletellus can be easily determined microscopically and is consistent with the type species' morphology (Smith & Thiers 1971). Corner (1972) and Pegler (1983) also adhered to a narrower definition of Boletellus characterized by spores that are longitudinally winged, ribbed, costate, or striate.
Here we describe Boletellus exiguus sp. nov., Boletellus dicymbophilus sp. nov., and Boletellus piakaii sp. nov. discovered in ectomycorrhizal (EM) Dicymbe (Fabaceae subfam. Caesalpinioideae) forests in Guyana. These 3 new species are placed in
Boletellus based on their olivaceous brown, longitudinally ridged basidiospores, dry pilei, tubulose, blue-staining hymenophores, and lack of clamp connections. We also give a new distribution record to Boletellus ananas (M.A. Curtis) Murrill var. ananas the type species for this genus which has never before been recorded from the Guiana Shield region.
24
Materials and Methods
Annual collecting expeditions were conducted during the May-July rainy seasons of 1998–1999, in the Upper Ireng River Basin along Guyana’s western border with Brazil in the west-central Pakaraima Mountains, and of 2000–2005, in the Upper Potaro River
Basin ~ 30 km north of the Ireng site. At each site fungi were collected within a five km radius of a previously established base camp in forests dominated by Dicymbe corymbosa
Spruce ex Benth. (Henkel 2003).
Basidiomata were examined in the field for their fresh characteristics. Color was subjectively described and recorded according to Kornerup and Wanscher (1978) with color plates noted in parentheses (e.g., 3C4). Macrochemical spot tests were performed following Singer (1986). Basidiomata were field-dried with silica gel beads.
Microscopic anatomical details were determined on fresh specimens at base camp with an EPOI microscope and in the laboratory using an Olympus BX51 microscope with bright field and phase contrast optics. Fungal tissue of dried specimens was rehydrated
and mounted in either H20, 3% KOH, or Melzer's reagent. For each taxon a minimum of
20 basidiospores, basidia, cystidia and other structures were measured. Line drawings
were made with a drawing tube, inked and scanned. Scanning electron micrographs of
basidiospores were obtained with either a Jeol JSM-6400 or Topcon ABT32 scanning
electron microscope using 200 kV. Specimens are deposited in the following herbaria as
indicated: BRG, HSU, and NY (Holmgren et al. 1990)
25
Taxonomy
Boletellus exiguus T.W. Henkel and Fulgenzi sp. nov.
Latin diagnosis: Pileus brunneus, juventute velutinus, postea subtiliter areolatus,
9−33 mm latus. Trama caerulescens ubi exposita. Stipes brunneus, subtiliter longitudinaliter striatus, cartilagineus, apice cum collo rubro, 7−34 × 1−4 mm.
Basidiosporae olivaceae in massa, amygdaliformes, longitudinaliter porcatae, 10−15 × 7−
9 µm. Fructificatio insidens trunco Dicymbe arborum.
HOLOTYPE: Henkel 8696 (BRG; ISOTYPE: HSU, NY; MycoBank #MB 511183)
Pileus 9−33 (42) mm broad, convex to applanate, dark brown (7D7) throughout
when young to chestnut brown (5D5−5E7) to yellow-tan (4E6) with age, velutinous,
becoming finely squamulose and areolate when mature, less so over disk, tacky to dry;
margin slightly inrolled when young, irregularly crenulate with age; trama 1−1.2 mm
thick at margin, 1−2 mm over tubes, 2−2.5 mm over stipe, dingy-white, bluing rapidly
with exposure, solid, less so with age. Odor minimal, pleasant; taste mild. Tubes 1−2 mm long at margin, 2−7 mm centrally, 2−5 mm at stipe, broadly and shallowly depressed around stipe, of irregular lengths, concolorous with pores, rapidly blue-green (26E7)
upon exposure; pores lemon yellow (3A7) when young, maturing to olive-yellow (4C7−
4C8), rapidly blue-green (26E7) with pressure, with prominent decurrent tooth 2−2.5 mm
long, 0.5−2 per mm, subangular, radially elongate near stipe. Stipe 7−34 × 1−4 mm,
subequal, gradually and slightly flaring to 2−4 mm at apex and base, typically curving
26 outward and upward from Dicymbe trunk, cartilaginous, tan (5D6) to maroon-brown
(10F6−10D8) throughout, with prominent red (10D8) zone over distal 1−2 mm of apex, darkening slightly upon handling, finely longitudinally striate; extreme base with brown tomentum; trama red-maroon (10F6−10F8) in upper half, tan-brown (5D5) below, unchanging.
Basidiospores olivaceous-brown (5F6−6F5) to dark olive-green (3F8) in medium to heavy deposit, 10−15 × 7−9 µm (mean 12.7 × 8.2 µm; n = 20), Q range = 1.2−2, (mean
Q = 1.53), olive-golden in H2O and KOH, inamyloid, amygdaliform, with moderately
thick single wall, uniguttulate, with 10−16 longitudinal ridges; ridges < 1 µm tall,
occasionally bifurcating, terminating at unequal lengths before the apex and thus leaving
a smooth area, all ridges converging at hilar appendage; hilar appendage 0.5−1 μm long.
Basidia 37−51 × 12−15 µm, subclavate, tapering gradually to base, hyaline in H2O and
KOH, with numerous refractive globules pale yellow in H2O, lighter in KOH, with 3 or 4
sterigmata; sterigmata 2−4 µm long. Pleurocystidia infrequent, 65−85 (100) × 14−20
µm, projecting 27−42 µm above the hymenial palisade, ventricose, thin-walled; wall
hyaline in H2O and KOH, with golden incrustations evident in Melzer’s. Hymenophoral
trama boletoid, strongly divergent; mediostratum 37−54.3 µm wide, of many thin,
slightly interwoven hyphae, these hyaline in H2O, gelatinized and hyaline in KOH, lateral
stratum hyphae 6.2−9.8 µm wide, hyaline in H2O and KOH, nongelatinized. Pileipellis a
derm consisting of angular cells with tufts of erect inflated terminal cells concentrated in
the squamules; tufts 91.4-197.6 µm wide, in mass orange-yellow in H2O, paler in KOH;
27 terminal cells 19.7−41.2 µm long, cylindrical or ventricose, rarely clavate or mucronate.
Pileus trama interwoven; individual hyphae 6.1−11 µm wide, light golden in H2O, hyaline in KOH, regularly septate. Stipitipellis a densely interwoven trichodermial palisade of cylindrical elements with inflated terminal cells, in mass golden-orange in
H2O, lighter in KOH; terminal cells projecting 24.7−38.3 µm, cylindrical to ventricose,
concentrated on stipe striations. Stipe trama of densely interwoven hyphae, these 2−4.9
µm wide, faint golden in H2O, hyaline in KOH. Clamp connections absent.
Macrochemical reactions: NH4OH immediately blood-red (9C8) on pileus, then fading within minutes to orange, negative on stipe and pores; KOH red-orange (9B8) on pileus then quickly becoming orange (6B8), red (8D8) on stipe; FeSO4 negative on pileus, dark
blue-green (25F4) on tube mouths then fading to a dark olive-green (26F5), darkening
stipe.
Habit, habitat, and distribution. Solitary to scattered among humic accumulations
on trunks of large, living Dicymbe corymbosa trees; known from the type locality in the
Upper Potaro River Basin and adjacent Upper Ireng River Basin of Guyana.
Etymology. Exiguus = small (Latin), referring to the diminutive basidiomata.
Specimens examined. GUYANA. REGION 8 POTARO-SIPARUNI: Pakaraima
Mountains, Upper Ireng River Basin; 1.5 km east of confluence of Sukabi and Ireng
Rivers, lower slope of Mt. Kukuinang, elevation 850 m, 6 June 1998, Henkel 6898 (BRG;
HSU); west bank of Yuarka Creek, 1 km upstream from confluence with Suruwabaru
Creek, elevation 800 m, 31 May 1999, Henkel 7088 (BRG; HSU), 15 June 1999, Henkel
28
7208 (BRG; HSU); Upper Potaro River Basin, within 5 km radius of 5o 18′ 04.8″ N, 59o
54′ 40.4″ W, elevation 710−750 m; vicinity of Potaro base camp, 26 May 2000, Henkel
7436 (BRG; HSU); 3 km southwest of Potaro base camp near Dicymbe plot 3, 29 July
2003, Henkel 8636 (BRG; HSU); in Dicymbe plot 3, 24 June 2004, Henkel 8696
(HOLOTYPE, BRG; ISOTYPE: HSU, NY); 1 km southeast of Potaro base camp, 28
May 2005, Henkel 8809 (BRG; HSU); 1 km west of Potaro base camp, 30 May 2005,
Henkel 8815 (BRG; HSU).
29
Figure 5. Basidiomata of Boletellus exiguus (HOLOTYPE; Henkel 8696). Bar = 10 mm.
Figure 6. Microscopic features of Boletellus exiguus (HOLOTYPE; Henkel 8696) a. Basidia. b. Pleurocystidia, in Melzer’s. c. Basidiospores. Bar = 10 µm.
30
Commentary. Boletellus exiguus is recognized in the field by its diminutive size, the chestnut-brown, squamulose and finely areolate pileus, irregularly angular pores that are lemon-yellow when young, rapidly blue-staining hymenophore, a red zone at the apex of a small curving stipe, and the habit of fruiting alone or in small groups on Dicymbe trunks. The masses of humus that accumulate between the epicormic shoots and roots of mature Dicymbe trees appear to be a required site for fruiting of B. exiguus, and are known to harbor abundant ectomycorrhizae (Woolley et al. 2007). A similar fruiting habit has been noted elsewhere for other Boletellus spp. (e.g. Boletellus emodensis
(Berk.) Singer, Boletellus ananas (M. A. Curt.) Murrill; Corner 1972; Singer et al. 1983) and is also recorded here for Boletellus dicymbophilus sp. nov. Microscopically B. exiguus is distinguished by having 3 or 4 sterigmate basidia with numerous pale yellow refractive globules, pleurocystidia with golden incrustations in Melzer’s, and a pileipellis of angular cells with tufts of erect inflated terminal elements.
Boletellus exiguus is best disposed infragenerically in Boletellus section
Chrysenteroidei Singer based on the absence of red tints on the pileus, the general lack of viscidity, and the absence of a marginal veil (Snell & Dick 1970; Singer 1986). The diminutive size of B. exiguus is similar to that of the boletelloid Boletus ridiculus Corner from Malaysia; B. ridiculus can, however, be distinguished from B. exiguus by its longer basidiospores (16−21 µm vs. 10−15 µm) and shorter pleurocystidia (40−60 µm vs. 65−85
(100) µm; Corner 1972). The distinctive red zone at the stipe apex of B. exiguus resembles the red annular band of Boletellus cubensis (Berk. & M. A. Curt.) Singer from the eastern Caribbean, but B. exiguus lacks an annulus; B. cubensis is also markedly
31 larger (pileus diam 20−60 mm vs. 9−42 mm, stipe length 30−70 mm vs. 7−34 mm; Pegler
1983, Singer et al. 1983). Among Congolian Boletellus spp. none are phenotypically close to B. exiguus (Heinemann & Goossens-Fontana 1954). Other members of
Boletellus that deviate from strictly 4-sterigmate basidia are Boletellus jalapensis (non sensu Murrill) Gilbert, and Boletellus obscurecoccineus (Höhn) Singer but otherwise these species do not phenotypically resemble B. exiguus (Corner 1972; Singer et al.
1983).
Boletellus dicymbophilus Fulgenzi & T.W. Henkel sp. nov.
Latin diagnosis: Pileus porphyreus, convexus vel planus, rugosus, velutinus, postea subtiliter areolatus, 19−48 mm latus; trama alba, immutabilis. Stipes brunneus, longitudinaliter striatus, ad tactum atrans, 41−60 (81) × 4−7 mm. Basidiosporae olivaceo-brunneae in massa, amygdaliformes, longitudinaliter porcatae, 12−15 × 8−11
µm. Fructificatio insidens trunco Dicymbe arborum.
HOLOTYPE: Henkel 8616 (BRG; ISOTYPE: HSU, NY; MycoBank #MB 511184)
Pileus 19−48 (82) mm broad, convex to planoconvex, red-brown (8E8− 9E8−
9F5) when immature, becoming brown (6E6−6F6) and then orange-tan (6C6) to yellow- tan (4C6) with age, rugulose to rugose throughout, velutinous, finely areolate with age
(under lens), moist, margin slightly inrolled and entire; trama 1−3 mm thick at margin, 2−
5 mm over tubes, 3−7 mm above stipe, white to cream, slightly browning with exposure, solid. Odor indistinct; taste mild. Tubes 1−6 mm long at margin, 5−13 mm centrally, 4−
32
8 mm at stipe, narrowly and shallowly depressed around stipe, with short decurrent tooth
1−2 mm long, concolorous with pores, instantly bluing (26E8) upon exposure, eventually darkening to brown; pores progressing from yellow (4A7−4B7) to orange-yellow (4C8−
5D8) to dark yellow (4A8−5B8), rapidly blue-green (26E7) with pressure, 0.5−1.5 per mm, isodiametric to angular with age. Stipe 41−60 (81) × 4−7 mm, equal, slightly enlarging at extreme base, red-brown (9D7−9E7) throughout, with handling becoming brown (7F6−7F7) to dark brown (8F5), finely longitudinally striate throughout, striations minutely pubescent (under lens), subreticulate at apex, base with brown (8F5) strigose hairs on lower 4−20 mm; trama brown (6E7−6F7) throughout to dark brown (7F7) to red- brown (8E4), unchanging, solid.
Basidiospores olive (4D6) to olivaceous brown (4F7) in light to heavy deposit;
12−15 × 8−11 µm (mean = 13 × 9 µm; n = 25), Q range 1.2 −1.7 (mean Q = 1.37), golden-olive in H2O and KOH, inamyloid, amygdaliform, usually uniguttulate, with 7−10
longitudinal ridges; ridges < 1 µm tall, dichotomously forked, occasionally non-forked,
terminating in unequal lengths near apex, at extreme base all ridges converging at hilar appendage; hilar appendage 1−1.5 µm long. Basidia 43−48 × 12−15 µm, clavate, thin-
walled, hyaline in H2O and KOH, with numerous refractive globules, these light golden in H2O, lighter in KOH; with 2, 3, or 4 sterigmata. Pleurocystidia frequent, 33−56 × 7−
12 µm, projecting 22−49 (57) µm beyond the hymenial palisade, arising from the
subhymenium, cylindrical to narrowly clavate; thin-walled, hyaline in H2O and KOH,
with minute amber incrustations at basal and apical portions evident in Melzer’s and
33
H2O. Hymenophoral trama boletoid, strongly divergent; mediostratum 37−59.3 µm
wide, of thin, slightly anastomosing hyphae, golden-orange in H2O, gelatinized and
lighter in KOH; lateral stratum hyphae 1.2−2.5 µm wide, hyaline in H2O and KOH,
nongelatinized. Pileipellis a two-layered trichodermial palisade, in mass golden in H2O, lighter in KOH; terminal cells 42−76.6 × 12.4−24.7 µm, most inflated and of variable shapes, oblong, cylindrical, napiform, vesiculate, to occasionally bluntly ventricose; penultimate cells interwoven, less inflated, hyaline in H2O and KOH, inamyloid. Pileus
trama interwoven; hyphae 6.2−12.4 µm wide, thin-walled, faint golden in H2O, hyaline
in KOH, regularly septate, with external dark burgundy acerose crystals evident in KOH,
Melzer’s, and H2O. Stipitipellis an interwoven trichodermial palisade of cylindrical
elements giving rise to inflated terminal cells, in mass golden in H2O, lighter in KOH;
terminal cells 40−66.7 (77) × 4.9−7.4 µm wide, thin-walled, cylindrical to aciculate;
hyaline in H2O and KOH, inamyloid. Stipe trama of densely packed longitudinal hyphae,
these 5−10 µm wide, hyaline in H2O and KOH, with external dark burgundy acerose
crystals evident in KOH, Meltzer’s, and H2O. Clamp connections absent.
Macrochemical reactions: NH4OH burgundy on pileus, orange on pileus trama,
burgundy on stipe base trama; KOH burgundy to orange on pileus, dark orange on pileus
trama, burgundy on stipe base trama.
Habit, habitat, and distribution. Solitary or in groups of 2−3 among humic
accumulations on trunks of large, living Dicymbe corymbosa trees; known only from the
type locality in the Upper Potaro River Basin of Guyana.
34
Etymology. Dicymbophilus = Dicymbe loving (Greek), referring to the exclusive fruiting habit on Dicymbe trunks.
Specimens examined. GUYANA. REGION 8 POTARO-SIPARUNI: Pakaraima
Mountains, Upper Potaro River, within 5 km radius of 5o 18′ 04.8″ N, 59o 54′ 40.4″ W,
elevation 710−750 m; Ayanganna airstrip, 20 May 2000, Henkel 7405 (BRG; HSU);
Dicymbe plot 2, 8 May 2000, Henkel 7455 (BRG; HSU); Dicymbe plot 2, 10 May 2000,
Henkel 7480 (BRG; HSU); Dicymbe plot 2, 23 June 2000, Henkel 7851 (BRG; HSU);
vicinity of Potaro base camp, 2 May 2001, Henkel 8011 (BRG; HSU); Dicymbe plot 1, 18
May 2001, Henkel 8152 (BRG; HSU); vicinity of Potaro base camp, 25 July 2003,
Henkel 8616 (HOLOTYPE, BRG; ISOTYPE: HSU, NY); vicinity of Potaro base camp, 5
July 2004, Henkel 8733 (BRG; HSU); vicinity of Potaro base camp, 31 May 2005,
Henkel 8818 (BRG; HSU); 1.5−2 km southeast of Potaro base camp, 1 July 2005, Henkel
8824 (BRG; HSU); 0.5−1 km west of Potaro base camp, 3 June 2005, Henkel 8829
(BRG; HSU); 2 km southeast of Potaro base camp, 5 June 2005, Henkel 8840 (BRG;
HSU).
35
Figure 7. Basidiomata of Boletellus dicymbophilus (Henkel 8818). Bar = 10 mm.
Figure 8. Microscopic features of Boletellus dicymbophilus (HOLOTYPE; Henkel 8616) a. Basidia. b. Pleurocystidia. c. Basidiospores. Bar = 10 µm.
36
Commentary. Boletellus dicymbophilus is distinctive due to its dark red-brown, rugose pileus that becomes lighter with maturation, its subequal, dark brown, longitudinally striate stipe, the yellow to olive-yellow, blue-staining hymenophore, the lack of a bluing reaction of the exposed trama, and the habit of fruiting singly or in groups of 2−3 on D. corymbosa trunks. Microscopically B. dicymbophilus is distinguished by its 2−4 sterigmate basidia with numerous pale yellow refractive globules, cylindrical to narrowly clavate pleurocystidia with amber encrusting pigments evident in H2O and Melzer’s, a 2-layered palisadic pileipellis of variously shaped
terminal elements, a palisadic stipitipellis of variably-shaped cylindrical elements, and
the presence of external burgundy acerose crystals in the pileus and stipe trama.
Boletellus dicymbophilus is best disposed infragenerically in Boletellus section
Chrysenteroidei Singer based on the dry pileus lacking red tints and the absence of a
marginal veil (Snell & Dick 1970; Singer 1986). Non-bluing trama has also been
reported for Boletellus longicollis (Ces.) Pegler & Young, B. obscurecoccineus (Corner
1972), and B. cubensis (Berk. & M. A. Curtis) Singer (Pegler 1983; Singer et al. 1983);
although only B. longicollis from Malaysia and Japan is otherwise phenotypically similar
to B. dicymbophilus, with dark brown rugose pilei, but the former has a well developed,
white, gelatinous appendiculate veil (Corner 1972; Imazeki et al. 1988). Other members
of Boletellus that deviate from strictly 4-sterigmate basidia are B. jalapensis, Boletellus
ivoryi Singer, and B. obscurecoccineus but each differs from B. dicymbophilus; for
example B. jalapensis has longer basidiospores (15−25 vs.12−15 µm) and B.
37 obscurecoccineus longer pleurocystidia (65−130 vs. 33−56 µm; Corner 1972; Singer et al. 1983). Boletellus dicymbophilus is similar to Boletellus pustulatus (Beeli) Gilbert from tropical Africa in basidioma stature, basidiospore size, and the presence of a 2- layered palisadic pileipellis of variously shaped hyphal elements. However, B. pustulatus possesses ventricose-rostrate pleurocystidia, cheilocystidia, and a bluing reaction in the exposed trama (Heinemann & Goossens-Fontana 1954, Watling & Turnbull 1992).
Boletellus piakaii T.W. Henkel & Fulgenzi, sp. nov.
Latin diagnosis: Pileus olivaceo-brunneus, rugosus et minute granulatus, 40−72
mm late; trama caerulescens ubi exposita. Stipes stramineus, apice cum collo porphyreo,
longitudinaliter porcatus, 98−120 × 7−9 mm. Basidiosporae olivaceo-brunneae in
massa, amygdaliformes, longitudinaliter porcatae, 9.8−12.4 × 5−7.4 μm.
Holotype: Henkel 8728 (BRG; ISOTYPE: HSU, NY) MycoBank MB 511936
Pileus (25) 40−72 mm broad, convex to planoconvex, dark brown (6F8)
throughout when young to olive brown (5E6−5E8−5F8) to olive-yellow (4A8−4B8−
4C8−4D8) with age, rugulose to rugose, minutely granular (under 10× lens), moist;
margin slightly inrolled and entire; trama 1−2 mm thick at margin, 3−5 mm over tubes,
6−12 mm above stipe, off-white, immediately green-blue (26D5) upon exposure, fading
to dingy-green (28D6) and yellowing after several minutes, solid. Odor minimal,
pleasant; Taste mild. Tubes 3−6 mm long at margin, 8−13 mm centrally, 6−7 mm at
stipe, of irregular lengths, narrowly and deeply depressed around stipe, with short
38 decurrent teeth 1−2 mm long, light olive-yellow (3A7−3B7), quickly blue-green (20F8−
24F8) upon exposure, eventually fading to dull brown; pores yellow (2A8) when immature to olive-yellow (3A7−3B7−4B8−4C8), immediately blue-green (24F8) with pressure, then fading gradually to green (27F8), green-brown (4E6), and eventually brown (6E8−6F8), 1−1.5 per mm, subisodiametric to angular. Stipe (60) 98−120 × 7−13 mm, subequal, enlarging gradually to 11−13 mm broad at base, ground tissue yellow-tan
(4A5−4B5−4C8), overlaid with pinkish brown (6D5−6E5−6D4−6E4) to red-maroon
(7E6−7E7−7D8−8E7) longitudinal striations throughout, these darkening with age and handling, apex with light red-brown (7A5) band, lower 20−25 mm with densely matted dark-brown (7F4−8F2) tomentum; subtending hyphae concolorous and often associated with ectomycorrhizal rootlets; trama off-white to yellow (4A7−4B7) to brown (7D5−
7E5−7D8−8E7) with age, transiently bluing upon exposure, solid.
Basidiospores dark olive-brown (4F8−5F8) in medium to heavy deposit, 9.8−12.4
× 5−7.4 μm (mean Q = 1.69), golden-olive in H2O and KOH, inamyloid, amygdaliform,
1−2 guttulate, with 18−22 longitudinal ridges; ridges < 1 µm tall, repeatedly
dichotomously forked, converging at both poles, transverse striae absent; hilar appendage
0.5−0.9 μm long. Basidia 32.4−46 × 13.1−15.6 μm, clavate, wall hyaline in H2O and
KOH, with numerous refractive globules, these light golden in H2O, lighter in KOH, 4-
sterigmate; sterigmata 3.2−5 μm long. Pleurocystidia 37−69 × 8.4−12.4 μm, ventricose-
rostrate, frequent, arising from the subhymenium, projecting 21−30.8 μm beyond the
hymenial palisade, hyaline, thin-walled. Cheilocystidia absent. Hymenophoral trama
39 boletoid, strongly divergent. Hymenophoral trama boletoid, strongly divergent; mediostratum 19.7−49.4 μm wide, of many thin-walled, nearly parallel hyphae, golden in
H2O, lighter and gelatinized in KOH, lateral stratum hyphae 7.4−12.4 μm wide, hyaline,
nongelatinized. Pileipellis a cystoderm of irregularly globose to subangular cells; these
thin-walled, faint-golden in H2O, hyaline in KOH. Pileus trama of interwoven hyphae,
many with thickened walls; individual hyphae 4.4−11.1 μm wide, wall up to 0.5 μm
thick, regularly septate, devoid of contents, in mass light golden in H2O, lighter in KOH.
Stipitipellis an interwoven trichodermial palisade of cylindrical elements with inflated terminal cells, in mass golden orange in H2O, lighter in KOH; terminal cells projecting
22.5−40 μm, cylindrical to clavate, occasionally ventricose to mucronate, these concentrated on longitudinal striations; subpellis hyphae interspersed with external
burgundy acerose crystals. Stipe trama of densely packed parallel hyphae, in mass faint
golden in H2O, lighter in KOH; individual hyphae 4−9.6 μm wide, hyaline in H2O and
KOH, regularly septate. Clamp connections absent. Macrochemical reactions: NH4OH rapidly light red-brown (8D6) on pileus, soon darkening, burgundy (9E8) on stipe ground, black on longitudinal striations, light burgundy (9D6) on stipe trama; KOH light orange-brown (7C6) to burgundy (8F7) on pileus, burgundy (8F7) on stipe, red-brown
(8D8) on pileus and stipe trama; FeSO4 dark grey-green (28F4) on pileus, dark green
(29F5) on tube mouths, dark green (28F8) on stipe, yellow-green (29D6) on stipe trama.
Habit, habitat, and distribution. Solitary to scattered on root mat in D.
corymbosa forest, rarely on lower base of D. corymbosa trunks; more frequent late in the
40 rainy season; known only from the type locality in the Upper Potaro River Basin of
Guyana.
Etymology. The species epithet recognizes the collector of the holotype, Piakai
Henkel.
Specimens examined. GUYANA. REGION 8: POTARO-SIPARUNI. Pakaraima
Mountains, Upper Potaro River, within a 5 km radius of ‘Potaro Base Camp’ (5o 18′
04.8″ N, 59o 54′ 40.4″ W, elevation 710−750 m); vicinity of Potaro base camp, 2 May
2001, Henkel 8013 (BRG; HSU); in Dicymbe plot 1, 9 May 2001, Henkel 8077 (BRG;
HSU), 2 July 2004, Henkel 8728 (HOLOTYPE, BRG; ISOTYPE: HSU, NY); 1 km west
of Potaro base camp, 30 May 2005, Henkel 8810 (BRG; HSU); 1.5 km southeast of
Potaro base camp on ‘Benny’s ridge’, 14 August 2007, Henkel 8869 (BRG; HSU); in
Dicymbe plot 2, 24 August 2007, Henkel 8878 (BRG; HSU); 0.75 km northeast of Potaro base camp between north end of ‘Benny’s ridge’ and ‘Leon camp’, 25 August 2007,
Henkel 8882 (BRG; HSU).
41
Figure 9. Basidioma of Boletellus piakaii (HOLOTYPE; Henkel 8728). a. Dorsal. b. Ventral. Bar = 10 mm.
Figure 10. Microscopic features of Boletellus piakaii (HOLOTYPE; Henkel 8728) a. Basidia. b. Pleurocystidia. c. Basidiospores. Bar = 10 µm.
42
Commentary. Boletellus piakaii is recognized in the field by its olive-brown rugose pileus, yellow-tan subequal stipe with maroon longitudinal striations, and a rapid bluing reaction of the bruised hymenophore and exposed trama. Microscopically B. piakaii is distinguished by having basidiospores that do not exceed 12.5 μm in length, basidia with long sterigmata and numerous golden refractive globules, a cystoderm pileipellis of irregularly globose to subangular cells, and numerous thick-walled hyphae in the pileus trama.
Within the genus B. piakaii is best disposed in Section Chrysenteroidei Singer
due to the longitudinally ridged basidiospores, dry pileus lacking in red tints, and the
absence of a veil (Snell & Dick 1970, Singer 1986). Boletellus piakaii is similar in
stature and shares the brown, rugose pileus reported for Boletellus longicollis (Ces.)
Pegler & T.W.K. Young from Malaysia and Japan; B. longicollis can be distinguished by its white, gelatinous, appendiculate veil and non-cyanescent trama (Corner 1972, Imazeki et al. 1988). Among other Malaysian boletelli only Boletellus fallax (Corner) Watling
non Singer has cyanescent trama and lacks an appendiculate veil; B. fallax otherwise differs from B. piakaii in having longer basidiospores (18−24 μm vs. 9.8−12.4 μm),
longer pleurocystidia (60−140 μm vs. 37−69 μm), a smaller stature (pileus diam 25−45
mm vs. (25) 40−72 mm, stipe length 22−70 mm vs. (60) 98−120 mm), and red tints in the
pileus (Corner 1972). Among Congolian Boletellus species none are similar to B.
piakaii; only Boletellus longipes Heinem. has a similar stature, but larger basidiospores
(12.7−16.2 × 7.2−8.5 μm vs. 9.8−12.4 × 5−7.4 μm), an orange stipe, and areolate pileus
43
(Heinemann & Goossens-Fontana 1954). The Central American Boletellus belizensis B.
Ortiz & T.J. Baroni and Boletellus domingensis B. Ortiz & Lodge lack marginal appendiculae and have a cyanescent reaction in the exposed pileus trama and bruised hymenophore, yet these species are dissimilar to B. piakaii in having smaller statures
(pileus diam 24−40 and 18−60 mm vs. (25) 40−72 mm, stipe length 60−70 and 27−55 mm vs. (60) 98−120 mm), larger basidiospores (12−14.4 × 5.6−7.2 and 12.8−16 × 5.6−8
μm vs. 9.8−12.4 × 5−7.4 μm) pruinose stipe ornamentations, and in lacking a rugulose to rugose pileus surface (Ortiz-Santana et al. 2007).
Boletellus ananas (M.A. Curtis) Murrill var. ananas Mycologia 1:10. 1909
≡ Boletus ananas M.A. Curtis Amer. J. Sci. Arts 6 : 351. 1848.
= Boletus coccineus Fr. Epic. Myc. 423. 1838, nom. illegit., non Bull. 1791.
≡ Strobilomyces coccineus Sacc., Syll. Fungorum 6: 50 1888 ut “Fr”.
≡ Boletellus coccineus (Sacc.) Singer in Singer et al. Beih. Nova Hedwigia 105: 6: 1992 ut “(Fr.)”.
= Boletus isabellinus Peck, Bull. Torrey Bot. Club 24: 146. 1897, nom. illegit., non Schwein. 1822.
= Strobilomyces pallescens Cooke & Massee in Cooke, Grevillea 18: 5 1889.
≡ Boletellus pallescens (Cooke & Massee) E.-J. Gilbert, Bolets. 107. 1931.
Pileus 33−74 mm wide, convex to planoconvex, with appressed to recurved squamules, red-brown (10B7−10D7) to red-tan (7D5−8D4−8E5) to pink (9A4−10B4) to pink-grey (10C4), vestiture concentrated and more squarrose on disk, extending out of
44 cream (1A2−3A2−3A3−4A3) to light orange-pink (7A3) to light pink-red (9A6) floccose ground; margin entire and clasping stipe when young, at maturity separating into triangular appendiculae, these 6−12 × 3−10 mm, buff white (5A3−5B4), occasionally faint pink; moist; trama 2−3 mm thick at margin, 7−10 mm over tubes, 11−18 mm centrally, buff white to light yellow (3A3), rapidly bluing (23C7) upon exposure, solid.
Odor non-descript; Taste mild. Tubes 1−5 mm long at margin, 10−20 mm centrally, 4−6
mm at stipe, broadly and deeply depressed around stipe, of irregular lengths, bright yellow (3A8) to olive yellow (2B7−3B7−3C7) to mustard yellow (4A8−4B8), rapidly
bluing (23C7) upon exposure. Pores concolorous with tubes, rapidly blue-green (23C8)
with pressure, 0.5−1.5 per mm, angular. Stipe 53−115 × 6−14 mm broad, subequal,
gradually enlarging toward base to 10−19 mm, apical portion cream (3A4) to pink (9A4),
middle portion finely longitudinally striate, striations darkening with handling, red-
lavender (11A6−11B4−11B7−11B8) to brown-red (9E8−10E8), lighter with age,
immediately above basal tomentum cream (3A2−3A4) with few striations; basal
tomentum of white strigose hairs over lower 6−50 mm, occasionally subtended by
ectomycorrhizal rootlets; trama white to buff-tan (5B4) to light yellow (3A4), slightly
bluing with exposure; solid.
Basidiospores olivaceous-brown (4D7-4E7-5E6−5F6) in medium to heavy
deposit, 17.5−22.2 × 6.4−8 µm (mean Q = 2.73), golden in H2O and KOH, inamyloid,
amygdaliform, one to multiguttulate; wall 0.5−1 µm thick, with 12−14 longitudinal
ridges; ridges < 1 µm tall, occasionally bifurcating, converging at poles, with minute
45 cross-striae; hilar appendage 0.3−1 μm long. Basidia 39−57 × 11−15 µm, clavate, wall hyaline in H2O and KOH, with numerous refractive globules, these faint golden in H2O and KOH, 4-sterigmate. Pleurocystidia 42−47 × 8−12 µm, ventricose-rostrate, slightly capitate, frequent, arising from the sub-hymenium, projecting 19.3−29.6 µm above the hymenial palisade, thin-walled, hyaline, devoid of refractive contents. Cheilocystidia
19−42 (51) × 5−11 µm, ventricose, cylindrical, to narrowly clavate, thin-walled, infrequent. Hymenophoral trama boletoid, strongly divergent; mediostratum 24.7−45.7
µm wide, of many parallel, slightly interwoven hyphae, faintly grey-yellow in H2O, lighter and gelatinized in KOH; lateral stratum hyphae 4.4−8.4 µm wide, hyaline and gelatinized in KOH, regularly septate. Pileipellis a densely interwoven trichodermial palisade of cylindrical elements with inflated terminal cells, in mass faint golden in H2O, lighter in KOH; terminal cells 23.5−51.9 × 9.4−16.8 µm, hyaline in H2O and KOH,
inamyloid, cylindrical to clavate, interwoven, concentrated on squamules. Marginal
appendiculae composed of wefts of interwoven inflated hyphae, some with faint golden spirally arranged encrusting pigments evident in H2O, KOH, and Melzer’s. Pileus trama
highly interwoven; individual hyphae 7.4−11.1 µm wide, hyaline in H2O, gelatinized and
hyaline in KOH, regularly septate. Stipitipellis a trichodermial palisade of cylindrical
elements with inflated terminal cells, in mass golden in H2O, lighter in KOH; terminal
cells projecting 30.4−63 µm, cylindrical to clavate, occasionally mucronate. Stipe trama
densely interwoven, in mass golden in H2O, lighter in KOH; individual hyphae 4.9−7.2
46
µm wide, hyaline in H2O and KOH, with spirally arranged faint golden encrusting
pigments, these evident in KOH, Meltzer’s, and H2O. Clamp connections absent.
Macrochemical reactions: NH4OH olivaceous yellow (4D6) on pileus, dirty yellow
(4C7) on tube mouths, bright red (10B8) on stipe, tan (6C4) on basal tomentum, yellow
on trama of pileus and stipe; KOH bleaching pileus ground, rusty-brown (7D8) on
squamules, orange-brown (5C6) on stipe, orange-yellow on pileus trama, burgundy to
orange on stipe trama; FeSO4 pink to faint grey on pileus, steel-grey on stipe; olive-green
(26F6) on tube edges.
Habit, habitat, and distribution. In Guyana typically fruiting singly or in pairs
within 1−2 m above ground level on D. corymbosa trunks, associated with
ectomycorrhizas within humic accumulations; rarely found fruiting on ground on heavily
decayed, root-penetrated wood; recorded from the Upper Potaro and Upper Ireng River
Basins in Guyana; also known from south-eastern North America, Central America, New
Zealand, Malaysia, and possibly Australia (Corner 1972, Singer et al. 1983).
Specimens examined. BRAZIL, AMAZONAS: Boletellus ananas var. minor,
Estrada Manaus-Caracarai, 4 April 1980, Singer B10913 (HOLOTYPE, INPA).
GUYANA, REGION 8, Potaro-Siparuni, Pakaraima Mountains, Upper Ireng River Basin,
west bank of Suruwabaru Creek, 1 km upstream from confluence with Yuarka creek, 2
March 1997, Henkel 6263- 6264; 23 May 1999, Henkel 7038; Upper Potaro River, within a 5 km radius of ‘Potaro Base Camp’ (5o 18′ 04.8″ N, 59o 54′ 40.4″ W, elevation 710−750
m); Ayanganna airstrip, 19 May 2000, Henkel 7400; vicinity of Potaro base camp, 30
June 2000, Henkel 7925; 4 km southwest of Potaro base camp near Dicymbe plot 3, 18
47
May 2001, Henkel 8168; vicinity of Potaro base camp, 25 July 2003, Henkel 8614, 5 July
2004, Henkel 8734, 31 May 2005, Henkel 8819; 2 km south of Potaro base camp, 2 June
2005, Henkel 8826; 0.75 km west of Potaro base camp, 3 June 2005, Henkel 8833.
Guyana collections housed in BRG and HSU.
48
Figure 11. Basidiomata of Boletellus ananas var. ananas. a. Henkel 8819. b. Fruiting habit on humic deposit of Dicymbe trunk, Upper Potaro Basin, Guyana. Bar = 10 mm.
Figure 12. Microscopic features of Boletellus ananas var. ananas (Henkel 8168) a. Basidia. b. Pleurocystidia. c. Basidiospores. Bar = 10 µm.
49
Commentary. Boletellus ananas var. ananas is recorded for the first time from northeastern South America. This striking bolete is recognized in the field by its red-pink squamose pileus, membranous marginal appen-diculae, bright yellow, rapidly blue- staining hymenophore, cyanescent trama, and tree trunk fruiting habit. These features are consistent with those of B. ananas var. ananas as described from other regions (McNabb
1967, Smith & Thiers 1971, Corner 1972, Singer 1986, Halling & Mueller 2005). Micro- scopically B. ananas var. ananas is distinguished by large basidiospores with cross striae on the ridges and spirally encrusted hyphae in the marginal appendiculae and stipe trama.We have not adopted the nomenclature erected by Singer et al. (1992: i.e.
Boletellus coccineus var. coccineus for Boletellus ananas var. ananas). Singer created this name in the mistaken belief that the earliest available name for the taxon was Boletus coccineus Fr. 1838. However, Fries’s name is an illegitimate later homonym (cf. Boletus coccineus Bull. 1791), and Singer’s combination is actually based on Strobilomyces coccineus Sacc. 1888. The earliest available name for the taxon is therefore Boletus ananas M.A. Curtis 1848, the basionym of Boletellus ananas.
Boletellus ananas var. ananas, as the type of the genus, is in Section Boletellus
Singer based on the squamose, dry pileus with red-pink tones, a marginal veil that clasps the stipe when immature, and longitudinally ridged spores that are > 16 µm long (Singer
1986). Most characters of the Guyana material other than host association are consistent with those previously reported for B. ananas var. ananas; one minor deviation is that the pleuro-cystidia of Guyana specimens are consistently shorter (< 50 µm) than those reported for collections from Malaysia (50−95 µm), and the Dominican Republic and
50
Belize (44−91.2 µm) (Corner 1972, Ortiz-Santana et al. 2007), but consistent with those of material from southeastern North America, New Zealand, and Costa Rica (McNabb
1967, Smith & Thiers 1971, Singer et al. 1983). Boletellus ananas var. ananas has consistently larger basidiomata than B. ananas var. minor Singer from Brazil and
Nicaragua, and lacks the thick-walled cheilocystidia of B. ananas var. crassotunicatus
Singer from Nicaragua and Panama and laciniate-reticulate stipe ornamentation of B. coccineus var. amarus Singer from Honduras and Belize (Singer et al. 1983, Singer et al.
1992, Ortiz-Santana et al. 2007).
The habit of fruiting on tree trunks has been reported for varieties of B. ananas from southeastern North America, Costa Rica, Brazil, Panama, Nicaragua, and Guyana
(Murrill 1909, Singer et al. 1983, this paper), although terrestrial fruiting has been reported in Malaysia (Corner 1972) and Central America (T. Baroni pers. comm.). Due to the typically elevated fruiting habit and occurrence on dead wood the ectomycorrhizal status of B. ananas has been debated, although all collections have been made in association with ectotrophic host trees including Pinus and Quercus spp. in southeastern
North America (Murrill 1909) and Central America (Singer et al. 1983, Halling &
Mueller 2005, Ortiz-Santana et al. 2007), Quercus humboldtii Bonpl. in Colombia
(Franco-Molano & Uribe-Calle 2000), various Fagaceae and Dipterocarpaceae spp. in
Malaysia (Corner 1972), and Leptospermum and Pinus spp. in New Zealand (McNabb
1967). In Guyana the humic deposits on Dicymbe trunks bearing B. ananas are consistently permeated with abundant ectomycorrhizas (Woolley et al. 2008).
51
Key to Boletellus species in Guyana
1a. Marginal veil present, becoming appendiculate; pileus squamose to squamulose, with pinkish tones ...... B. ananas var. ananas
1b. Marginal veil absent; pileus squamulose or otherwise, lacking pinkish tones 2
2a. Fruiting terrestrial, rarely on tree trunks; pileus > 46 mm broad; stipe > 98 mm long;
basidiospores not exceeding 12.5 × 7 µm...... B. piakaii
2b. Fruiting on tree trunks; pileus < 45 mm broad; stipe < 80 mm long; basidiospores up to 15 × 11 µm ...... 3
3a. Basidiomata small; pileus 9−33 mm broad; stipe 7−34 × 1−4 mm; pleurocystidia
infrequent, ventricose, 65−85 (100) × 14−20 µm ...... B. exiguus
3b. Basidiomata larger; pileus 19−34 mm broad; stipe 41−60 (80) × 4−7 mm;
pleurocystidia frequent, cylindrical to narrowly clavate, 33−56 × 7−12 µm
...... B. dicymbophilus
52
Figure 13. Scanning electron micrographs of basidiospores of Boletellus species from Guyana. a. Boletellus exiguus (HOLOTYPE; Henkel 8696), ×6700. b. Boletellusexiguus (Henkel 8809), ×8900. c. Boletellus dicymbophilus (Henkel 8824), ×3200. Bar = 1 µm.
Figure 14. Scanning electron micrographs of basidiospores of Boletellus species from Guyana. a. Boletellus piakaii (Henkel 8013) ×4000. b. Boletellus ananas var. ananas (Henkel 8168) ×6300.
CHAPTER 3
FISTULINELLA CINEREOALBA SP. NOV AND NEW DISTRIBUION RECORDS FOR AUSTROBOLETUS FROM GUYANA
Abstract: Fistulinella cinereoalba sp. nov., Austroboletus rostrupii, previously
known from Southeast Asia, and Austroboletus festivus from Brazilian Amazonia are
described for the first time from Guyana. These boletes were collected from tropical
forests dominated by ectomycorrhizal Dicymbe spp. (Fabaceae subfamily
Caesalpinioideae) in the Pakaraima Mountains of western Guyana.
Key Words: Boletaceae, Dicymbe, ectomycorrhizal fungi, Guiana Shield,
Neotropics
Introduction
In monodominant stands of Dicymbe (Fabaceae subfamily Caesalpinioideae, tribe
Amherstieae) in the Pakaraima Mountains of Guyana Boletaceae (Boletales,
Basidiomycota) taxa are a prominent component of the ectomycorrhizal fungal assemblage (Henkel 1999; Henkel et al 2002; Fulgenzi et al 2007; Fulgenzi et al 2008;
Mayor et al 2008). This paper describes three species occurring within two genera,
Austroboletus (Corner) Wolfe and Fistulinella Henning, that are infrequently encountered in Dicymbe forests.
Fistulinella encompasses ~27 species most of which have a tropical distribution
(Pegler & Young 1981; Pegler 1983; Singer et al 1983; Singer 1986; Watling & Gregory
1989; Watling 2008). Fistulinella has been variably defined and recognized (Wolfe
53 54
1979; Pegler & Young 1981; Wolfe 1982; Pegler 1983; Singer 1986; Watling &
Gregory 1989; Lewis & Cibula 2000; Redeuilh & Soop 2006; Watling 2008). Here we use the diagnostic features of Fistulinella defined by Watling (1989; 2008) as bolete species with basidiospores that are smooth, elongate, and pink-brown, cinnamon-brown to purple brown in deposit, with some or all showing a weak to strong pseudoamyloid reaction, a strongly gelatinized lateral stratum in the tube trama, a pileipellis that is a trichodermium, ixotrichodermium or ixocutis, a basidioma that is viscid to glutinous, and a white hymenophore that is pink to pink-grey with maturation (Pegler & Young 1981;
Pegler 1983; Singer 1986; Watling 2008).
Austroboletus contains ~ 40 species with primarily tropical distributions with some species occurring in the temperate northern and southern hemispheres (McNabb
1967; Wolfe 1979; Horak 1980; Singer et al 1983; Singer 1986; Watling & Gregory
1986; Watling & De Meijer 1987; Watling & Lee 1999; Halling et al 2006). We use the morphological concept of Austroboletus as boletes with basidiospores that are lightly to heavily ornamented with pits, warts, or reticulations, and are flesh-pink, vinaceous-brown to rust-brown in deposit (Wolfe 1979; Pegler & Young 1981).
Here we describe Fistulinella cinereoalba sp. nov. and new distribution records for Austroboletus rostrupii (Corner) Wolfe, previously known from Southeast Asia, and
Austroboletus festivus (Singer) Wolfe from Brazilian Amazonia. These boletes were collected from tropical forests dominated by ectomycorrhizal Dicymbe spp. (Fabaceae subfamily Caesalpinioideae, tribe Amherstieae) in the Pakaraima Mountains of Guyana.
55
Materials and Methods
Collecting expeditions were conducted during the May-July rainy season of 1999 in the Upper Ireng River Basin (5o 05′ N, 59o 58′ W) along Guyana’s western border with
Brazil in the west-central Pakaraima Mountains, and annually during May-July of 2001–
2004 in the Upper Potaro River Basin (5o 18′ 04.8″ N, 59o 54′ 40.4″ W) ~ 30 km north of
the Ireng site. At each site fungi were collected within a five km radius of a previously
established base camp in forests dominated by Dicymbe corymbosa Spruce ex Benth.
(Henkel 2003).
Basidiomata were examined in the field for their fresh characteristics. Color was
subjectively described and recorded according to Kornerup and Wanscher (1978) with
color plates noted in parentheses (e.g., 3C4). Macrochemical spot tests were performed
following Singer (1986). Basidiomata were field-dried with silica gel beads (Miller et al
2002).
Microscopic anatomical details were determined on fresh specimens in the field at the base camp with an EPOI microscope and in the laboratory using an Olympus BX51
microscope with bright field and phase contrast optics. Fungal tissue of dried specimens
was rehydrated and mounted in either H20, 3% KOH, or Melzer's reagent. For each
taxon a minimum of 20 basidiospores, basidia, cystidia and other structures were
measured. Line drawings were made with a drawing tube, inked and scanned. Scanning
electron micrographs of basidiospores were obtained with a Topcon ABT32 scanning
56 electron microscope using 15 kV or 30 kV. Specimens are deposited in the following herbaria as indicated: BRG, HSU, and NY (Holmgren et al 1990).
Taxonomy
Fistulinella cinereoalba Fulgenzi and T.W. Henkel sp. nov.
Pileus griseus, fibrillosus, aequus, glutinosus, 19-43(55) mm latus. Stipes albus, brunneus ubi contusum, gelatinosus, squamis ubique tenuibus, erectis, 55-80 x 3-6(13) mm. Hymenophorum brunneum ubi contusum. Basidiosporae cinnamomeo-brunneae, subfusiformae, leves, omnino pseudoamyloideae, 12.4-19.8 (24.8) x 3.7-4.9 µm. Basidia
4- sterigmatibus. Pleurocystidia cylindricea ad aciculate.
HOLOTYPE: Henkel 8471 (BRG; ISOTYPE: HSU, NY)
Pileus 19−43 (55) mm broad, convex, dark grey (6D2−6E2) throughout initially,
lighter grey (4C2−4C4) with age, matted-fibrillose over white ground (under hand-lens),
overlain by a gelatinous pellicle throughout, glutinous, viscid in dry weather; margin
entire, slightly in-rolled when young; trama 0.5−1.5 mm thick at margin, 3−5 mm over
tubes, 12−14 mm over stipe, white, solid. Odor mildly fungal; taste mild. Tubes 2−4
mm long at margin, 6−8 mm centrally, 10−12 mm at stipe, narrowly and strongly
depressed around stipe, of irregular lengths, concolorous with pores, slightly browning
upon exposure; pores white when young, maturing to light pink-grey (7B3−7C3), slightly
browning with pressure, 1.5−3 per mm, isodiametric to subovate. Stipe 55−80 × 3−6 (13)
mm, subequal, gradually and slightly tapering inward at base, entirely white, browning
57 slightly with handling, with fine erect scales imbedded in a dense gelatinous pellicle throughout; extreme base with fine white hyphal cords, and occasionally with subtending concolourous ectomycorrhizae; trama white, solid, unchanging.
Basidiospores cinnamon-brown (7D8−7E8) in heavy deposit, 12.4−19.8 (24.8) ×
3.7−4.9 µm, Q mean (range) = 3 (2.5−4 (7)), light yellow-pink in H2O, lighter in KOH,
most exhibiting a yellow, light red, or burgundy dextrinoid reaction, subfusiform, uni- to
multiguttulate, smooth; hilar appendage 0.2−0.5 μm long. Basidia 27.2−34.6 × 9.8−12.4
µm, narrowly clavate, hyaline in H2O and KOH, often with granular contents, 4-
sterigmate; sterigmata 1.5−3.5 µm long. Pleurocystidia frequent, 37.1−61 × 3.7−6.2 µm,
projecting 18.5−24.7 (44.5) µm above the hymenial palisade, aciculate to cylindrical,
occasionally with granular contents, thin-walled, hyaline in H2O and KOH.
Cheilocystidia frequent, cylindrical, projecting 44.5−84 µm, with 2−3 septa, slightly
interwoven in lower 2/3. Hymenophoral trama boletoid, strongly divergent;
mediostratum (19.8) 24.7−61.7 µm wide, of many thin, highly interwoven hyphae, these
hyaline in H2O and KOH, gelatinous in KOH; lateral stratum hyphae 2.5−5 µm wide,
hyaline in H2O and KOH, gelatinous in KOH. Pileipellis a trichodermium superimposed
on a trichodermial palisade of the ground, all overlain by the gelatinous pellicle; terminal cells of trichodermium cylindrical, with 1−3 septa, orange-grey in H2O, lighter in KOH,
projecting 49.4−86.5 µm from pileus trama, of irregular lengths; terminal cells of
trichodermial palisade clavate, hyaline in H2O and KOH, projecting 12.4−32.1 µm from
pileus trama; pellicle (14.8) 24.7 − 123 (217.5) µm thick, hyphae interwoven, periclinal,
58 gelatinized, 2.4−6.1µm wide, in mass orange-grey in H2O, lighter and more gelatinous in
KOH, with external burgundy acerose crystals. Pileus trama highly interwoven; individual hyphae 4.9−7.4 µm wide, hyaline in H2O and KOH, gelatinous in KOH.
Stipitipellis with concentrated tufts of slightly interwoven, inflated cylindrical elements immersed in a dense pellicle of thin-walled, gelatinous hyphae; cylindrical elements with
1−3 septa, projecting 69.2−84 µm from stipe trama, concentrated on stipe scales; pellicle
74.1−173 µm thick, pellicle hyphae 2.5−3.7 µm wide, in mass light yellow in H2O, paler and gelatinous in KOH. Stipe trama of densely interwoven hyphae, these 2.5−4.9 µm wide, hyaline in H2O and KOH. Clamp connections absent. Macrochemical reactions:
NH4OH nil on pileus.
Habit, habitat, and distribution. Infrequent, solitary or in small groups of 2−3 on
root mat in forests dominated by Dicymbe corymbosa, known only from the type locality
in the Upper Potaro Basin of Guyana.
Etymology. Cinereo = grey (Latin), alba = white (Latin), referring to the
distinctive grey pileus and white stipe.
Specimens examined. BRAZIL. AMAZONAS: Fistulinella campinaranae var.
scrobiculata, Estrada Manaus-Caracarai, 12 Jan 1979, Singer 12089 (HOLOTYPE of
variety, INPA). GUYANA. REGION 8 POTARO-SIPARUNI: Pakaraima Mountains,
Upper Potaro River Basin, elevation 710−750 m; vicinity of Potaro base camp, 4 June
2000, Henkel 7441 (BRG; HSU), Dicymbe plot 3, 5 May 2001, Henkel 8030 (BRG;
59
HSU), 12 May 2001, Dicymbe plot 3, Henkel 8108 (BRG; HSU), vicinity of Potaro base camp, 17 June 2002, Henkel 8471 (HOLOTYPE, BRG; ISOTYPE: HSU, NY).
60
Figure 15. Basidiomata of Fistulinella cinereoalba. a. HOLOTYPE (Henkel 8471). b. Field habit, Upper Potaro Basin, Guyana. Bar = 10 mm.
Figure 16. Microscopic features of Fistulinella cinereoalba (HOLOTYPE; Henkel 8471) a. Basidia. b. Pleurocystidia. c. Basidiospores. d. Cheilocystidia. Bar = 10 µm.
61
Commentary. Fistulinella cinereoalba is recognized in the field by its glutinous grey pileus contrasting with the white, glutinous stipe, pink-grey hymenophore that browns slightly with handling, and small to medium stature. Fistulinella cinereoalba is distinguished microscopically by its smooth, subfusiform basidiospores exhibiting a range of pseudoamyloid reactions, aciculate to cylindrical pleurocystidia, cylindrical septate cheilocystidia, and gelatinous pellicle covering the stipitipellis and pileipellis.
This new species in placed into Fistulinella Henn. because it is consistent with the accepted diagnostics for the genus as defined by Pegler & Young (1981), Pegler (1983);
Singer (1986); and Watling (2008). Infragenerically F. cinereoalba fits well in section
Fistulinella Singer due to its viscid to glutinous pileus and stipe (Singer 1986).
Fistulinella cinereoalba resembles Fistulinella campinaranae var. scrobiculata
Singer from Brazil by virtue of its viscid to glutinous basidioma with a grey pileus, a white stipe, and similarly shaped and sized basidiospores (Singer et al 1983). These taxa differ in that F. campinaranae var. scrobiculata has basidiospores that only exhibit a pseudoamyloid reaction in ½ of the wall, 2 or 4 sterigmate basidia, pleurocystidia which are fusoid to ventricose to ampullaceous, a hymenophore unchanging with pressure, a glabrous and unchanging stipe, and a scrobiculate-rugose pileus (Singer et al 1983).
Fistulinella cinereoalba is similar to Fistulinella lutea Redeuilh & Soop from
New Zealand in basidioma stature, basidiospore shape and size, the presence of septate cheilocystidia, and a pileipellis covered by a pellicle of gelatinous hyphae; however, F. cinereoalba differs in lacking a yellow pileus and stipe, lacking basidiospores with minute depressions as seen in light microscopy, and having longer cheilocystidia (44.5−
62
84 µm vs. 40−55 µm; Redeuilh & Soop 2006). Among described Congolian boletes and
Malaysian “Tylopiloid” species in Corner’s Group 1 with a viscid pileus, none are phenotypically close to F. cinereoalba (Heinemann & Goossens-Fontana 1954; Corner
1972).
Austroboletus rostrupii (Syd. & P. Syd.) Horak, Sydowia 33: 82. 1980.
≡ Boletus rostrupii Syd. & P. Syd., Ann. Mycol. 1: 177. 1903, nom. nov.
≡ Boletus lacunosus Rostrup, Bot. Tidsk. 24: 357. 1902, non Otth in Trog, Bern. Mittheil.
37. 1857.
= Boletus mucosus Corner, Boletus in Malaysia, 77. 1972.
≡ Austroboletus mucosus (Corner) Wolfe, Biblio. Mycol. 69: 107. 1979.
Pileus 55−95 mm broad, convex to applanate, dark brown (6E8−7F8) throughout to orange-brown (6C8−6D8), covered in a glutinous pellicle; margin entire and clasping stipe when young, at maturity separating into triangular appendiculae, these eventually sloughing with age; trama 1 mm thick at margin, 12 mm over stipe, white, unchanging, solid. Odor minimal; taste mild. Tubes 5 mm long at margin, 14 mm centrally, strongly depressed around stipe, of irregular lengths, concolorous with pores, slightly browning upon exposure; pores white to cream when young, maturing to dull pink (6A2−6B2), slightly browning with pressure, isodiametric, 1−1.5 per mm. Stipe 100−147 (195) × 11−
18 mm, subclavate, gradually enlarging to 18 mm at base, white to cream throughout, covered in a glutinous pellicle, coarsely reticulate to lacunose-canaliculate throughout,
63 reticulations 1−3 mm tall, these turning dark brown (6E8−7F8) to orange-brown (6C8−
6D8) with handling; extreme base with fine white hyphal cords; trama white, unchanging, solid, becoming hollow near base with age.
Basidiospores pink-brown (9D6−9E6) in heavy deposit, 14−17 × 4−8 µm, Q mean (range) = 3 (2.5−3.5), yellow-pink in H2O and KOH, inamyloid, subfusiform,
uniguttulate, highly warted over the middle, outer 1/5 of ends smooth; hilar appendage
0.1−0.3 μm long. Basidia 27.7−39.5 × 12.4−15.6 µm, clavate, strongly tapered towards
base, hyaline in H2O and KOH, occasionally with granular contents, 4-sterigmate;
sterigmata 2.5−4.9 (6.2) µm long. Pleurocystidia frequent, (50.6) 69.2−94.8 × 7.4−12.4
µm, projecting (24.7) 37−55.8 µm above the hymenial palisade, ventricose-rostrate, occasionally cylindrical, with 1 or less frequently 2 transverse septa occurring in upper
2/3, occasionally with granular contents in upper 2/3, thin-walled, hyaline in H2O and
KOH. Hymenophoral trama boletoid, strongly divergent; mediostratum 34.6−49.4 µm
wide, of many thin-walled slightly interwoven gelatinized hyphae, these light yellow in
H2O and KOH; lateral stratum hyphae 3.7−4.9 µm wide, hyaline and gelatinized in H2O and KOH. Marginal appendiculae of highly interwoven wefts of thin-walled hyphae interspersed with hyphal elements with inflated terminal cells, hyaline in H2O and KOH,
hyphae 4.9−9.8 µm wide; terminal cells 15−17.8 × 5−8 µm, spathulate to petaloid,
hyaline in H2O and KOH, occasionally with granular contents. Pileipellis a dense
ixocutis of highly interwoven, periclinal, thin, gelatinous hyphae, 29.6−46.9 µm thick; individual hyphae 3−5 (8.6) µm wide, tawny yellow and gelatinous in H2O and KOH.
64
Pileus trama interwoven; individual hyphae 2.5−4.9 µm wide, light yellow in H2O, hyaline in KOH. Stipitipellis covered in a dense pellicle of thin, highly interwoven, periclinal, gelatinous hyphae, 16.8−24.7 µm thick, interspersed with areas of compact,
anticlinal cylindrical elements on the reticulations and clavate cells elsewhere, in mass
light yellow in H2O, lighter in KOH; cylindrical elements, with 1−3 septa in upper ¾,
projecting (51.9) 100−148.2 µm, slightly interwoven in lower ¼, concentrated on
reticulations, hyaline in H2O and KOH; clavate cells projecting 17.3−49.4 µm, in
depressions between reticulations. Stipe trama highly interwoven, individual hyphae
4.2−7.6 µm wide, hyaline in H2O and KOH. Clamp connections absent. Macrochemical
reactions: NH4OH immediately bright blue-green on pileus, then fading rapidly to dull
burgundy, unchanging on stipe, light blue on stipe base.
Habit, habitat, and distribution. In Guyana fruiting in the early rainy season,
solitary but frequent, apparently absent later in the rainy season; on root mat in forests
dominated by D. corymbosa in the Upper Potaro and Ireng River Basins of Guyana; also
known from Thailand, Singapore and Malaysia.
Specimens examined. GUYANA. REGION 8 POTARO-SIPARUNI:
Pakaraima Mountains, Upper Ireng River Basin, elevation 850 m, east bank of
Suruwabaru creek, 0−2 km from Ireng base camp, 28 May 1999, Henkel 7065 (BRG;
HSU); Upper Potaro River Basin, elevation 710−750 m; 4 km upstream from Ayanganna
airstrip, 29 April 2001, Henkel 8003 (BRG; HSU); in Dicymbe plot 3, 5 May 2001,
Henkel 8032 (BRG; NY; HSU); 3−4 km east of Potaro base camp, 11 May 2001, Henkel
65
8093 (BRG; HSU); 3−4 km southeast of Potaro base camp, 19 May 2001 Henkel 8189
(BRG; HSU).
66
Figure 17. Basidiomata of Austroboletus rostrupii. a. Henkel 8189. b. Field habit, Upper Ireng Basin, Guyana. Bar = 10 mm.
Figure 18. Microscopic features of Austroboletus rostrupii (Henkel 8189) a. Basidia. b Basidiospores. c. Pleurocystidia. Bar = 10 µm.
67
Commentary. Austroboletus rostrupii is a distinctive bolete recognized in the field by its glutinous, orange-brown pileus with marginal appendiculae, white to pink hymenophore, and long, strikingly lacunose-reticulate stipe. Here we concur with Wolfe
(1979) in recognizing the species in Austroboletus (Corner) Wolfe based on the generic diagnostics of a flesh-pink, vinaceous-brown to rust-brown spore print, and basidiospores that are heavily pitted, warted, or reticulate (Wolfe 1979; Pegler & Young 1981; Singer
1986). Infragenerically A. rostrupii is assigned to section Austroboletus (Group 1 of
Singer 1986) because of its lacunose-reticulate stipe and centrally warted basidiospores
(Wolfe 1979). The specimens from Guyana agree both macro- and micro- morphologically with those previously described (Rostrup 1902; Corner 1972; Horak
1980; Watling & Hollands 1990; Watling & Lee 1999). The septate hymenial cystidia seen in the Guyanese specimens have not been reported previously (Rostrup 1902;
Corner 1972; Horak 1980; Watling & Hollands 1990; Watling & Lee 1999).
Additionally, the dramatic blue-green pileus reaction to ammonia exhibited by the
Guyanese specimens was not assessed elsewhere. Other boletes redescribed from
Guyanese specimens have exhibited minor variations in macro- or microscopic characters compared with collections from distant localities (e.g. Tylopilus ballouii, T. eximius,
Boletellus ananas var. ananas; Henkel 1999; Fulgenzi et al 2007; Mayor et al 2008).
Such morphological variances may reflect geographic structuring of distant populations and possibly cryptic speciation (Halling et al 2008).
Septate cystidia have been reported for Austroboletus novae-zelandiae (McNabb)
Wolfe, Austroboletus eburneus Watling & N.M. Gregory, and Austroboletus occidentalis
68
Watling & N.M. Gregory (McNabb 1967; Horak 1980; Watling & Gregory 1986). Of these, only A. novae-zelandiae from Australasia is phenotypically similar to A. rostrupii, with similar shape and size of the cystidia and basidia, and also sharing the warted basidiospores and lacunose-reticulate stipe. These species differ in that the pilei of A. novae-zelandiae are usually dry, cinnamon-brown, and squamulose to rimose-areolate, and its basidiomata are smaller than those of A. rostrupii (pileus 25−60 mm, stipe 50−100 mm vs. pileus 55−95 mm, stipe 100−147 (195) mm). Additionally, the basidiospores of
A. novae-zelandieae are consistently wider (8−9.5 (10.5) µm vs. 4−8 µm) and its grey- rose pileus reaction with NH4OH and red auto-oxidation in the stipe context are lacking
in A. rostrupii (McNabb 1967; Horak 1980).
The occurrence of A. rostrupii in Guyana greatly increases the known geographic
and host range of this putatively ectomycorrhizal species, previously unknown from the
Neotropics. The species has been collected in dipterocarp forests in Thailand (Rostrup
1902) and subsequently Singapore) and Malaysia (Corner 1972; Horak 1980; Watling &
Hollands 1990; Watling & Lee 1999), and now with caesalpinioid hosts in Guyana. All
collections of A. rostrupii in Guyana coincide with the onset of the main rainy season
which is consistent with the early monsoon fruiting phenology of A. rostrupii in Asia
(Horak 1980; Watling & Lee 1999).
Austroboletus festivus (Singer) Wolfe Biblthca. Mycol. 69: 92 (1979).
≡ Porphyrellus festivus Singer, Univ. Recife Inst. Mic. Publ. 304:18. 1961.
69
Pileus 18−54 mm broad, convex to planoconvex, dark red-brown (8D8−8E8) throughout, densely matted-fibrillose near center becoming minutely squamulose and areolate near margin, with white ground, dry; margin entire, in-rolled; trama 1−2 mm thick at margin, 6−8 mm over stipe, white, unchanging, solid. Odor minimal; taste minimal. Tubes 1−3 mm long at margin, 10−12 mm centrally, 3−5 mm at stipe, depressed around stipe, with slight decurrent tooth, concolorous with pores, unchanging; pores white to pale orange-cream (5A2−5A3) at maturity, unchanging with pressure, isodiametric, 2−3 per mm. Stipe 42−110 × 3−10 mm, equal, gradually and slightly enlarging towards base, extreme apex smooth, white, otherwise with tan-grey to pink- grey (6B2−7B3) fibrils, these more concentrated toward base; basal tomentum rose- burgundy (11B6−11C8) to burgundy (11D6−11E7); trama white to grey-green (28E5) at base, unchanging, solid.
Basidiospores dull flesh (5B3−5B4) in light deposit to orange-brown (5E7) in heavy deposit, 12.6−17.5 × 4.7−7.4 µm, Q mean (range) = 2.6 (2−3.3), light yellow-pink in H2O and KOH, inamyloid, subfusiform, uni- to multiguttulate, finely reticulate
throughout; hilar appendage 0.2−1 μm long. Basidia 28.4−40.3 × 11.1−13.6 µm, clavate,
strongly tapered toward base, hyaline in H2O and KOH, occasionally with granular
contents, 4-sterigmate; sterigmata 1.7−4.9 µm long. Pleurocystidia frequent, 37−44.5 ×
7.9−13.3 µm, projecting 15.3−17.3 µm above the hymenial palisade, ventricose to
narrowly obclavate, thin-walled; hyaline in H2O and KOH. Cheilocystidia of cylindrical
elements in concentrated tufts projecting 36.6−66.7 µm, elements with rounded tips and
70 occasionally with 1 or rarely 2 septa in upper 2/3. Hymenophoral trama boletoid, strongly divergent; mediostratum 14.8−29.6 µm wide, of thin-walled, anastomosing, gelatinized, regularly septate hyphae, these 2−5 µm wide, light yellow in H2O and KOH; lateral stratum hyphae 3.5−5 µm wide, thin-walled, hyaline and highly gelatinized in H2O and KOH. Pileipellis a trichodermium with tufts of inflated, erect, slightly interwoven cylindrical elements; tufts 111.2−345.8 µm wide; cylindrical elements of irregular lengths, 24.7−197.6 µm long, with 2−3 septa in upper 2/3, occasionally with basal or
penultimate cell more inflated than ultimate cell, ultimate cell 5−12.4 µm wide,
penultimate cell 12−19.8 µm wide, light yellow-brown in H2O and KOH. Pileus trama
interwoven; individual hyphae 4.4−5.4 µm wide, light yellow in H2O, lighter in KOH.
Stipitipellis with tufts of erect, inflated cylindrical elements that are more concentrated
and robust approaching base; tufts 25−345.8 µm wide; cylindrical elements of unequal
lengths, 49.4−140.8 × 4.4−5.4 µm, with 2−3 septa in upper 2/3, interwoven in lower 1/3.
Stipe trama interwoven, individual hyphae 4.2−7.6 µm wide, regularly septate, light
yellow in H2O and KOH, with scattered, external orange-red acerose crystals . Clamp connections absent. Macrochemical reactions: NH4OH negative on pileus and pileus
trama, yellow to orange-red on stipe and stipe trama; KOH negative on pileus, yellow on
pileus trama and tube trama, orange (6A5) on stipe and stipe trama; FeSO4 olivaceous-
yellow (4D7) on pileus, blue-green (25E6) on pileus trama and tube trama, negative on
stipe and stipe trama.
71
Habit, habitat, and distribution. In Guyana infrequently encountered during the
May-July rainy season, solitary or in groups of 2−3 on root mat in forests dominated by
D. corymbosa. Also reported from eastern and southeastern coastal Brazil (Singer 1961;
Singer 1986; Watling et al 1997).
Specimens examined. GUYANA. REGION 8 POTARO-SIPARUNI:
Pakaraima Mountains, Upper Potaro River Basin, elevation 710−750 m; vicinity of
Potaro base camp, 17 May 2001, Henkel 8164 (BRG; HSU), vicinity of Potaro base camp, 4 July 2004, Henkel 8732 (BRG; HSU).
72
Figure 19. Basidiomata of Austroboletus festivus. a. Henkel 8164. b. Mature specimen, Upper Potaro Basin, Guyana. Bar = 10 mm.
Figure 20. Microscopic features of Austroboletus festivus (Henkel 8164) a. Basidia. b. Pleurocystidia. c. Basidiospores. d. Cheilocystidia. Bar = 10 µm.
73
Commentary: Austroboletus festivus is easily recognized in the field by its red- brown, fibrillose, squamulose-areolate pileus, pale orange-cream hymenophore, and a stipe that is increasingly covered by tan-grey to pink-grey fibrils from the apex to the base, terminating in a rose-burgundy basal tomentum. We concur with Wolfe (1979) in placing this species in Austroboletus (Corner) Wolfe as it fits the generic diagnostics in having a spore print that is flesh-pink, vinaceous-brown to rust-brown, and basidiospores that are pitted, warted, or reticulate (Wolfe 1979; Pegler & Young 1981; Singer 1986).
Infragenerically A. festivus fits into Group 3 of Singer (1986) but bridges the boundaries of sections Graciles and Austroboletus erected around temperate taxa by Wolfe (1979); its stipe ornamentation is that of section Graciles, but basidiospore ornamentation that of section Austroboletus.
Austroboletus festivus specimens from Guyana are generally consistent macro- and micromorphologically with those previously described from Brazil (Singer 1961;
Wolfe 1979; Singer 1986; Watling & De Meijer 1997). However, the basidiospores of
Guyanese specimens are more strongly reticulate with pronounced anastamosing ridges under light-microscopy and SEM than the Brazilian material (Singer 1961; Wolfe 1979;
Singer et al 1983; Watling & De Meijer 1997). Such variation may reflect divergence in geographically distant populations (> 3000 km), or greater variability in basidiospore ornamentation in A. festivus than previously recorded (Henkel 1999; Halling et al 2008;
Fulgenzi et al 2007; Mayor et al 2008).
74
Figure 21. Scanning electron micrographs of basidiospores. a. Austroboletus rostrupii (Henkel 8189). b. Fistulinella cinereoalba (HOLOTYPE; Henkel 8471). c. Austroboletus festivus (Henkel 8164). Bar = 1 µm.
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