The North American species of Pholiota, by Alexander H. Smith and L. R. Hesler.

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The North American Species of Pholiota

best. Pileus cutis a thick gelatinous layer of interwoven yellowish to
hyaline smooth hyphae 2-5 pL diam.; hypodermium of rusty brown
hyphae (but color dissolving out and layer merely yellowish finally),
hyphae 5-17 /A diam. Context hyphae hyaline and with "colloidal" content as revived in KOH, 6-15 p. diam., yellowish in Melzer's reagent,
walls thin to slightly thickened and refractive in KOH. Clamp connections present.
HABIT, HABITAT, AND DISTRIBUTION: On trunks and logs of hardwood
(maple, basswood, elm, sycamore, beech, birch) and conifers, New York,
North Carolina, Tennessee, Michigan, Colorado, Idaho, Washington,
Oregon, New Mexico; Canada (Ontario); Europe, England; also reported from California (Overholts 1927), and Illinois (Harper, 1911);
June-November.
OBSERVATIONS: This species is marked by its viscid, yellowish to
tawny pileus, with appressed spot-like scales, and a dry stipe with fibrillose, recurved scales which tend to be more numerous downward. The
spores usually do not exceed 9.5 pu in length, only rarely reaching 10-11 pe.
Generally, it is not found at the base of trunks and stumps, but on them.
Lange (1938) has proposed P. aurivella var. cerifera (Karsten)
Lange for a variety which has a stipe with dense, recurved scales, which
at first are whitish but soon brownish from the base upward. We have not
distinguished this variant here in North America. P. caespitosa might
appear close but it has yellow scales on the stipe and when young a
whitish pileus. The brown bodies in the hymenium can be basidia,
basidioles, or cystidia, so a distinction between cystidia and basidia on
colored content is not made here. The pleurocystidia are a distinctive
feature of the species, but revive poorly. Moser's (1950) report of P.
squarroso-adiposa, to judge by the spore width, applies to P. aurivella.
The microscopic data given in the following account are from a
specimen from Derek Reid, collected at Berkhamsted, England. Oct. 27,
1955.
Spores 7-10(11) X 4.5-6 pu smooth, apical pore distinct but apex
not truly truncate; shape in face view broadly elliptic, in profile broadly
elliptic to obscurely bean-shaped, color in KOH dull tawny, in Melzer's
reagent reddish cinnamon; wall about 0.4.u thick.
Basidia 25-30 X 6-8 pE, 4-spored, clavate, hyaline in KOH and
yellowish in Melzer's reagent. Pleurocystidia embedded, 26-34 X 7-12 Eu,
sharply fusoid to clavate mucronate, wall thin smooth and hyaline; content "empty" except for a small at times poorly formed refractive inclusion. Cheilocystidia 22-33 x 5-9 p,, subfusoid, subfilamentous or fusoidventricose; walls smooth, yellow to hyaline, thin; content homogeneous,
yellow to hyaline. Caulocystidia in tufts (20) 33-65 X (8) 12-20 pu, clavate
to vesiculose-pedicellate; walls smooth to roughened, yellowish to hyaline;
content-"empty."
Gill trama of mostly floccose hyphae subparallel and with long
greatly inflated (20+ p.) cells, walls smooth, slightly thickened and re