The North American Species of Pholiota
106. Pholiota aurivelloides Overholts, Annals Missouri Bot. Garden 14: 151. 1927.
Hypodendrum aurivelloides Overholts, North Amer. Fl. 10: 281 1932.
Illustrations: Text figs. 214-217.
Pileus 5-8 cm broadly campanulate to convex, ferruginous to tawny, margin paler, slightly viscid, with a few spot-like or appressed scales. Context rather thick, yellow.
Lamellae sinuate-adnate or with a decurrent tooth, whitish then ochraceous-tawny or russet, medium close or slightly distant, broad (7 -12 mm).
Stipe 4-8 cm long, 5-10 mm thick, yellowish or brownish, more or less scaly, the scales sometimes somewhat gelatinous, equal, solid.
Spores 8-11 (11.5) x 6-7 (8) µ, smooth, wall ±0.3 µ thick, apical pore present and in larger spores often causing spore apex to appear somewhat truncate, elliptic in face view and also in profile or in profile varying to slightly bean-shaped, color in KOH yellowish-tawny, more cinnamon in Melzer's reagent.
Basidia 4-spored, 27-36 x 6-8 µ, clavate, hyaline to yellowish in KOH and in Melzer's reagent. Pleurocystidia abundant, 1) mostly clavate-mucronate, 25-36 x 8-12 µ, with thin smooth hyaline walls (in KOH), with a small highly refractive amorphous body not coloring in Melzer's reagent: 2) obtusely fusoid cells 30-48 x 6-11 µ and with brownish to ochraceous wrinkled content becoming dark amber-brown in Melzer's. Cheilocystidia 26-50 x 6-15 µ, versiform; clavate, subelliptic, inflated-vesiculose and at times capitate, or fusoid-ventricose, yellow to hyaline in KOH, walls typically thin and content homogeneous or resembling that of either type of pleurocystidia. Caulocystidia scattered, clavate up to 80 x 22 µ, and some with yellow to reddish homogeneous content in KOH.
Gill trama of floccose parallel hyphae with elongate thin-walled smooth inflated (finally) cells up to 15 µ diam., hyaline to yellowish in KOH, and many with highly refractive septa; subhymenium gelatinous-narrow and of interwoven narrow (2 µ) hyaline hyphae. Pileus cutis a thick gelatinous pellicle of hyphae 3-6 µ diam., walls thin smooth and hyaline, over this occur patches of amber-brown gelatinous hyphae 4-9 µ wide (representing the gelatinous scales); hypodermial region not distinct from content. Context hyphae inflated (6-15 µ ±), walls thin smooth, hyaline to yellowish. All hyphae inamyloid. Clamp connections present.
Habit, Habitat, and Distribution: On dead trees or from wounds in Alnus, Salix or Betula, Colorado, New Mexico, and Wyoming, late summer and fall. Type studied.
Observations: Our microscopic data in the above description are taken from Gruber 749, preserved at Michigan. The spores average broader than for P. aurivella, and there is a distinct difference in the pleurocystidia as described. Brown imbedded basidioles were not found in the type by us but were reported by Overholts, who was an accurate observer. Since these cells are generally present through the P. adiposa group in varying numbers even on basidiocarps in a single collection we are inclined not to give any taxonomic emphasis to their relative abundance in our treatment of this group.
Material Examined: COLORADO: Bartholomew (type). NEW MEXICO: Barrows 791. UTAH: McKnight F-144. WYOMING: Overholts.