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

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The North American Species of Pholiota

Spores 7-10 (12) x 4-5 (6) pu smooth, apical pore distinct and apex
obscurely truncate, shape in face view mostly ovate varying toward elliptic, in profile somewhat inequilateral; dull ochraceous tawny to cinnamon
in KOH, paler and more ochraceous in Melzer's reagent.
Basidia 20-26 x 5-7.5 p., 4-spored (some 2-spored) clavate, yellowish
in KOH, in Melzer's reagent duller yellowish. Pleurocystidia scattered,
36-52 x 9-12 p,, fusoid-ventricose, smooth, thin-walled, content often
ochraceous and coagulated (as revived in KOH). Cheilocystidia 28-43 X
6-7 pu, versiform: fusoid-ventricose, subfusoid, to nearly clavate, thinwalled, smooth (or soon becoming so in KOH), content yellow to
hyaline. Caulocystidia 38-66 X 4-8 pu and elongate, narrowly clavate
ventricose, rostrate, subfusoid or 33-40 x 9-14 pu and utriform, mostly
with yellowish walls in KOH, walls smooth and thin to slightly thickened.
Gill trama a somewhat interwoven strand of floccose hyphae 4-14 p.
diam.; walls thin, yellowish in KOH and smooth; subhymenium a well
developed layer of gelatinous narrow (1.5-3 pi wide) interwoven filaments
giving rise at base of basidia to a palisade of septate hyphae each of
which has a basidium as the terminal cell. Pileus cutis a thick layer of
rusty brown hyphae 2.5-4 pA or more in diam. with incrusting bands and
spirals of pigment, layer only subgelatinous in KOH, (space between
hyphae slightly more refractive than normal for a non-gelatinous cutis);
beneath this a hypodermial region of more enlarged (up to 12 /.) hyphae
with thin yellow smooth walls. Context hyphae paler down to a ferruginous band (in KOH) of cells with somewhat thickened walls just above
the subhymenium, the color intense in young caps. Clamp connections
present. All hyphae inamyloid.
HABIT, HABITAT, AND DISTRIBUTION: On hummocks, in sphagnum,
Michigan, Ohio and Tennessee, September-October. Type studied.
OBSERVATIONS: The habitat, medium large spores, projecting pleurocystidia, and scaly, tawny pileus disc are distinctive features of this
species. The yellow context at maturity, and yellow young gills and
stipe-apex, separate it from P. sphagnicola.
The anatomy of the apical pore of the spore is interesting in this
species. There is a very slight inflation of the outer wall layer right
around the pore which gives the apex a slightly different appearance than
in other species of Pholiota. A second rather deceiving feature of the
species is the almost pseudoparenchymatic band of cells with slightly
thickened walls next to the subhymenium; in young material revived in
KOH they are ferruginous red but in older caps almost colorless. This
sort of pigment change has also been observed in Psathyrella species. In
some older pilei areas of hymenium had apparently been destroyed by
insects, and numerous pleurocystidia had replaced the basidia.
MATERIAL EXAMINED: MICHIGAN: Harding 391, 409, 432; Smith
33-1014, 33-1041, 988, 4921, 50585, 62203, 64746; OHIO: 20076 (CU)
TENNESSEE: Hesler 10930.