Mycologia, 78(5), 1986, pp. 861-865. 1986, by The New York Botanical Garden, Bronx, NY 10458

HEBELOMA ARENOSA (, CORTINARIACEAE), A NEW SPECIES FROM LAKE STATES NURSERIES

H. H. BURDSALL, JR.

Center for Forest Research, USDA, Forest Service, Forest Products Laboratory,1 One Gifford Pinchot Drive, Madison, Wisconsin 53705-2398

J. S. MACFALL

Plant Pathology Department, University of Wisconsin, Madison, Wisconsin 53706

AND

M. A. ALBERS

Minnesota Department of Natural Resources, Grand Rapids Regional Office, 1201 East Highway 2, Grand Rapids, Minnesota 55704

Since the late 1960’s, a species of Hebeloma arenosa Burdsall, MacFall, and Al­ has been frequently observed in nursery beds bers, sp. nov. FIGS. 1-4 (one tree species per bed) of 2- and 3-year-old Differt a Hebeloma speciebus pileis (2-)3-5(-6)cm Picea glauca (Moench) Voss. (white spruce), Pic­ diam, aurantiobrunneis vel fusco; stipitibus 20-50 × ea abies (L.) Karst. (Norway spruce), Pinus re­ 2-5 mm, albis, annulis destitutis, bases usque ad 15 sinosa Ait. (red pine), and Pinus strobus L. (east­ mm diam, contextis miscellis arena; odorati Raphano; em white pine) throughout Wisconsin. Croghan basidiospores subellipsoideis vel navicularibus, ferru­ (1984) reported it from nursery beds of Picea gineis, rugulosis (9.5-)10-13(-14)× 5-7 µm; cheilo­ cystidias frequens, cylindraceis vel ventricosis, apice abies, Picea mariana (Mill.) B.S.P. (black spruce), globose. Crescens solo arenoso, pleurumque plantulis and Pinus banksiana Lamb. (jack pine) in both conifers in America boreocentralis. Minnesota and Wisconsin. Albers (1976) dem­ HOLOTYPE: JSM 1, on sandy soil in nursery bed of onstrated that it is a mycorrhizal symbiont with Pinus resinosa Ait., Wilson Nursery, Boscobel, Grant County, Wisconsin, September, 1984, coll. J. S. MacFall red pine in culture and stated that because of its (BPI); isotype (CFMR). abundance it may be an important mycorrhizal associate in the Great Lakes States. Comparison Pileus (2-)3-5(4)cm diam, convex with in- of these specimens with those of similar Hebe­ curved margin when young, slightly concave with loma species indicates that those from the nurs­ upturned incised margin in age, surface greyish ery beds represent a new species. orange (5B3) to brownish orange (near 5C5), oc­ Specimens were studied using freehand sec­ casionally orange grey (5B2) or as dark as light tions of basidiocarps revived in 2% KOH. Color brown (6B6), darker on disc and paler to nearly notations in parentheses are those of Kornerup white towards margin, glabrous, viscid, frequent­ and Wanscher (1967); other color names are not ly with adhering sand. Context white, thin, some­ standardized. Cultures were grown for study on what pliant, with raphanoid odor when crushed. 1.5% potato dextrose agar (PDA) (Tuite, 1969: Lamellae adnexed, yellowish grey (3B2) or grey­ 53). ish yellow (4B3) to brownish orange (3C4-5) in age, moderately close, medium broad. 2­ 5 × 0.5-1.5 cm, slightly tapered at base, dirty 1 Maintained at Madison, Wisconsin, in cooperation white to cream color, pubescent, most dense to­ with the University of Wisconsin. ward the apex but less so below, annulus lacking,

861 862 MYCOLOGIA

1 FIGS. 1-4. Hebeloma arenosa (JSM 4, holotype). 1. Basidiocarps, /2 natural size. 2. Scanning electron mi­ crograph of basidiospores, × 3500. 3. Photomicrograph of basidiospores, x 1500. 4. Photomicrograph of chei­ locystidia and single basidiospore, × 1500. often with hyphal mass and sand adhering to low, giving rise to clusters of caulocystidia. Cau­ base, with pith present in young specimens, be­ locystidia arising from stipitipellis (FIG. 4) 40­ coming hollow in age. 50 × 7.5-9 µm, cylindrical to subventricose, Basidiospores (FIGS. 1, 2) (9.5-)10-13(-14)× hyaline, thin-walled, smooth. Stipe context of 5-7µm, ovoid, adaxially flattened, brownish yel­ interwoven hyphae, 4-9(-12)µm diam, thin- low, uniguttulate, rugose, light brown (5D8) in walled, hyaline, smooth, septate, sometimes deposit. Basidia clavate, 31 × 9.5 µm, hyaline, swollen between septa. Clamp connections pres­ thin-walled, 4-sterigmate. Cheilocystidia (FIG. 3) ent at most septa throughout the basidiocarp. numerous, 35-53 x 8-11 µm, samewhat ven­ tricose to nearly clavate, sometimes with a dis­ HABIT, HABITAT, AND DISTRIBUTION: Caespitose, in tinct terminal swelling, hyaline, thin-walled. conifer seedling nursery beds. Known from the north central United States. Fruiting occasionally in the spring Pleurocystidia lacking. Pileipellis a gelatinous but more frequently in the late summer or fall. Usually layer ca. 500 µm thick, containing interspersed, the most prolific species fruiting. smooth, brown-walled hyphae (an ixotricho­ OTHER SPECIMENS EXAMINED: As H. arenosa: Wis­ derm); hyphae 2.5-4 µm diam, frequently flat­ consin: JSM 2, 3, 5, 6, 7, 8, associated with P. resinosa, Wilson Nursery, Boscobel, Grant County; JSM 4, as­ tened and folded, and appearing degenerated. Pi­ sociated with Picea abies, Griffith Nursery. Wisconsin leus trama of interwoven hyaline hyphae; hyphae Rapids, Wood County (all in CFMR and MPPD). As 4-8 µm diam, thin-walled, hyaline with regularly H. colvini Peck: New York sand hills near West Al­ distributed septa. Hymenophoral trama of bany, October (holotype, NYS). As H. colvini var. ve­ somewhat interwoven hyphae; hyphae 4-6 µm latum Peck New York gravelly ground under cotton­ wood trees, Rouses Point, September (holotype, NYS). diam, thin-walled, hyaline. Stipitipellis of par­ As H. crustuliniforme: Alaska: OKM 7859, associated allel hyphae; hyphae 2.5-4 µm diam, thin- to with Salix sp., Mendenhall Lake, Tongass National firm-walled (Burdsall, 1985), hyaline to pale yel­ Forest, August 2, 1969 (VPI) TABLE I COMPARISON OF HEBELOMA ARENOSA WITH SIMILAR HEBELOMA SPECIES (DISTINGUISHING CHARACTERS UNDERLINED) 864 MYCOLOGIA

Observations. -Hebeloma arenosa is a represen­ dase; reverse tan to yellowish cream in center, tative of subgenus Hebeloma Kumm., Section pale grayish cream at margin. Denudata (Fr.) Sacc. Its characteristics are sim­ ilar to those described for several other Hebe­ Hyphal characteristics. -Hyphae with abundant loma species in that group. The most similar clamps, 2.5 µm diam, hyaline, thin-walled, lack­ description is that of H. colvini Peck with the ing any specialized structure; not fruiting in cul­ basidiospores reported as 10-12× 5-6 µm (Peck, ture within 6 months. 1910 Kauffman, 1918) and “.0004'-.0005' long” Temperature relations. -Optimum, 24 C, 19-23 in the original description (Peck, 1879). We found mm in 14 da: average mat diam in 14 da (8 the basidiospores of the type specimen to mea­ replications) at constant temperature is as fol­ sure 13-17 × 7.8-8.5 µm and to differ in orna­ lows: 16 C, 8-10 mm; 28 C, 15-18mm; 32 C, mentation and shape from the rougher, subellip­ no growth. soid to navicular basidiospores of H. arenosa. Hebeloma crustuliniforme is also similar to H. Culture studied. -M-1 (deposited in ATCC) iso­ arenosa. The former possesses weeping gills, cy­ lated from cap tissue. Basidiospore germination lindrical cystidia and basidiospores with thinner has not been obtained. We know of no infor­ walls, however, and more granular ornamenta­ mation on cultural characteristics of other species tion than H. arenosa. in the Cortinariaceae to compare with our find­ Hebeloma arenosa is the only Hebeloma ings, and neither J. M. Trappe, Forestry Sciences species that we have observed occurring regularly Laboratory, Corvallis, Oregon, nor O. K. Miller, in Lake States nursery beds. It is distinguished Jr. (pers. comm.) are aware of such information. from other Hebeloma species by its spore size, We thank Drs. M. J. Larsen, Center for Forest shape, and ornamentation, stipe shape, and ap­ Mycology Research, FPL, Madison, WI, for pro­ parently restricted occurrence in conifer seedling viding the Latin diagnosis, O. K. Miller, Jr., De­ nursery beds where it fruits abundantly. Major partment of Biology, VPI&SU, for lending spec­ differencesamong other similar species are listed imens and providing the data regarding microscopic characters of H. hiemale, and J. H. in TABLE I. Hebeloma arenosa has been shown to form Haines (NYS) for loan of specimens. Drs. Larsen, mycorrhizal associations in flask cultures (Al­ D. F. Farr and G. M. Mueller are thanked for bers, 1976) and in nurseries (J. G. Berbee, De­ their critical comments on the manuscript. partment of Plant Pathology, University of Wis­ We also acknowledge the grant to Dr. J. G. consin, pers. comm.). Hyphae have been traced Berbee from the Department of Natural Re­ from sporophoresto conifer seedling roots in the sources, State of Wisconsin, to support this study. nursery. Further studies are being carried out to Key Words: Hebeloma, Agaricales, Cortinariaceae, determine the importance of H. arenosa as a culture, mycorrhizae. mycorrhizal symbiont (Berbee, pen. comm.). Dr. A. H. Smith and the late Dr. L. R. Hesler confirmed H. arenosa as a new species. It is in­ LITERATURE CITED cluded in an unpublished Hebeloma manuscript by them and is considered conspecific with spec­ imens from Oregon. We have not studied the Oregon specimens and thus have not included them in our concept. Cultural characteristics. -Growthvery slow to slow, 19-23mm in 14 da on PDA at 24 C; mat at 14 da white, soft, appressed-downy, azonate, with few aerial hyphae; margin regular at first but samewhat irregular at 14 da, white, with no noticeable odor; not reacting with syringaldazine spot test but a pink reaction on inoculum when

H2O2 added, indicating the presence of peroxi­ BRIEF ARTICLES 865