The North American Species of Pholiota

109. Pholiota hiemalis sp. nov.

Illustrations: Text figs. 497-499; pl. 51a, 51b.

Pileus 4-11 cm latus, obtusus demum plano-umbonatus, glutinosus, squamulosus; squamulae gelatinosae, latae, agglutinatae; laete luteus. Contextus cartilagineus, cum "FeSO₄" olivaceo; sapor mitis. Lamellae pallidae demum luteae, acie laete luteae, confertae, latae. Stipes 4-9 cm longus, 6-12 (15) mm crassus, luteus, squamulosus. Sporae 7-9 (10) x 4-4.5 (5) µ; cheilocystidia fusoide ventricosa vel clavata, laete luteae. Specimen typicum in Herb. Univ. Mich. conservatum est; legit prope Upper Priest Lake, Boundary Co., Idaho. 13 Oct. 1966. Smith 74173.

Pileus 4-11 cm broad, obtusely conic when young, the margin incurved, expanding to plano-umbonate, the surface very slimy, at first with 1-3 rows of broad flattish pale dull fulvous gelatinous scales which soon become washed off in wet weather, ground color dull yellow ochre over disc, lemon-yellow near the margin. Context cartilaginous, watery yellowish, odor unpleasant but soon fading, taste mild, FeSO₄ slowly olive.

Lamellae pallid when young but with yellow margins, becoming dull yellow and finally dull cinnamon brown but edges remaining bright yellow, close, broad, adnate becoming adnexed, not staining when bruised.

Stipe 4-9 cm long, 6-12 (15) mm thick at apex, enlarged down to a flaring base, stuffed with a pallid pith, soon rusty brown in the base and over it, surface finely recurved-squamulose over basal area with dry fibrillose squamules, medial portion with at first scattered rusty brown gelatinous patches or scales similar to those on pileus, silky to silky fibrillose above from the remains of an inner cortinate veil, at times this veil leaving a fairly thick loosely fibrillose annulus or annular zone.

Spores dull rusty brown in deposit, 7-9 (10) x 4-4.5 (5) µ, smooth; apex furnished with a small germ pore; shape in face view elliptic to ovate, in profile elliptic to obscurely bean-shaped; color in KOH pale dull tawny, in Melzer's sol. the same color or paler ochraceous, wall about 0.25 µ thick.

Basidia 17-22 x 4-5 µ, 4-spored, subcylindric to narrowly clavate, yellowish, hyaline in KOH and slightly more ochraceous in Melzer's sol. Pleurocystidia scattered, 30-50 x 8-15 µ, clavate-mucronate to clavate, content hyaline fresh but revived in KOH yellowish and wrinkled, in Melzer's the content in granules or irregular bodies and dull brown. (Not true chrysocystidia as far as content is concerned). Cheilocystidia versiform, clavate to vesiculose and 18-26 x 10-14 µ; narrowly clavate to fusoid-ventricose or utriform and 26-40 x 9-13 µ, some irregular or with one or two protuberances in upper part, with both a yellow content and wall (in KOH) when fresh, as revived with a distinctly yellow somewhat thickened wall in basal area or lower half, the upper part hyaline to yellowish and the wall thinner.

Gill trama with a central area of more or less parallel hyphae hyaline to yellowish in KOH and Melzer's, the hyphal cells inflating to 10-15 µ, the cells greatly elongated; subhymenium of gelatinous hyphae diverging to the hymenium and often with yellow content as revived in KOH, no incrusted hyphae noted. Pileus cutis a thick layer of gelatinized hyphae 3-7 µ diam., rather tangled in arrangement, the hyphal walls breaking down somewhat, the hyphae hyaline to ochraceous in KOH; hyphae of the gelatinous veil material breaking down almost completely (found as patches over the cutis); hypodermial region of hyphae with inflated cells (up to 20 µ) but walls hyaline to nearly so in KOH, in Melzer's the content of some cells ochraceous to orange. Context of hyaline hyphae with inflated cells hyaline in KOH and hyaline to dull ochraceous orange in Melzer's reagent, walls smooth and thin to slightly thickened in some ("double"). Clamp connections regularly present.

Habit, Habitat, and Distribution: Gregarious-caespitose on log of Abies (fir), Upper Priest River Boundary County, Idaho, Oct. 13, 1966. Smith 74173, type.

Observations: The distinguishing features of this species are its habitat on conifer logs, the large flat gelatinous scales on the pileus which finally disintegrate to dark brown discolorations which are not at all scale-like, the pallid young gills with their bright yellow margins, and the gelatinous as well as dry patches and squamules on the stipe. The spores are too large for P. adiposa. P. abietis appears to be closest and is abundant in the area, but does not have colored gill edges, and the scales on the pileus usually show as aggregations of appressed fibrils. In P. abietis the spores are 5.5-7 x 3.5-4 µ, i.e. slightly smaller.

P. hiemalis is a late-fruiting species, if one season is any indication. The type collection consisted of a log covered by the bright colored basidiocarps. Only a small amount of it was collected on Oct. 13th. That night a hard freeze came in the area, and I went back the next day to see what the remaining specimens were like. They were still frozen stiff at 10 o'clock in the morning. I gathered the remainder on the log and took them back to the laboratory. When set up for spore deposits they thawed out and deposited spores just as the unfrozen material had done from the day before. In the dried condition the frozen and unfrozen basidiocarps are indistinguishable. This is one reason for assuming that the fungus is a late fruiting species. It has apparently adjusted to nights. Most other fungi in the woods had collapsed from the frost by noon that day.

Pholiota muelleri (Fr.) P. D. Orton is described as having gills with edges yellower than the faces at times, but Orton describes the scales of the pileus as being fibrillose rather than gelatinous. He also describes the spores as 5-7 x 3-4 µ.