The North American Species of Pholiota
98. Pholiota rigidipes Peck, New York State Mus. Bull. 157: 31. 1912.
Illustrations. Text figs. 192-195.
Pileus 4-8 cm broad, broadly convex, sometimes slightly and broadly umbonate, pale yellow or buff, viscid; with obscure appressed fibrillose, brownish squamules which are more conspicuous in the center; obscurely striate when dried. Context thin, white, tinged yellow next to the lamellae; taste mild.
Lamellae adnexed or adnate, brownish ferruginous when mature, close, rather broad (3-6 mm), thin.
Stipe 5-9 cm long, 4-6 mm thick, white and pruinose at the apex, pallid and floccose-squamulose below, or nearly glabrous, rigid, flexuous, equal, stuffed or hollow. Veil leaving an evanescent annulus.
Spores 6-8 x 4-4.5 µ, smooth, apical pore distinct but apex not truncate; shape in face view oblong to elliptic, in profile much the same but a shade narrower, rarely slightly bean-shaped; color in KOH near pale ochraceous tawny, in Melzer's reagent paler and more ochraceous; wall about 0.25 µ thick.
Basidia 4-spored, 26-30 x 6-7 µ, ochraceous in KOH, paler in Melzer's reagent, narrowly clavate. Pleurocystidia 30-40 x 8-14 µ, clavate-mucronate to clavate, more rarely somewhat fusoid-ventricose, content tawny in KOH in most but some hyaline and evenly refractive, mostly buried in hymenium (no true chrysocystidia seen). Cheilocystidia small, 18-27 x 5-9 µ, obscurely fusoid-ventricose to suboblong-pedicellate to obtusely fusoid, walls smooth, thin, content hyaline to yellow. Caulocystidia 30-52 x 6-10 µ, clavate, capitate or mucronate, hyaline to yellow or pale tawny, walls smooth and thin.
Gill trama with a central strand of yellow subparallel floccose hyphae 3-9 µ diam., with walls smooth and swelling slightly in KOH, content not highly colored in Melzer's reagent; subhymenium a broad well defined gelatinous layer of narrow (2-3 µ) hyaline hyphae. Pileus trama with a zone of inflated hyphae (almost parenchyma-like in sections) walls in KOH 1.5-2 µ thick, and with a middle line showing as if two walls were fused, above this the cells with somewhat thickened walls, this type extending to the cuticular region and all hyphae ochraceous in KOH; cuticle a thick layer of subgelatinous hyphae 3-5 µ diam., smooth-walled, patches of tawny fibrils above this (from the veil) and these not gelatinous but some of the end-cells cystidioid and 42-56 x 6-12 µ. Clamp connections present. All hyphae inamyloid (none with orange to red content in Melzer's reagent).
Habit, Habitat, and Distribution: On the ground, probably on buried or exposed wood, New York, New Jersey and Missouri, September. Type studied.
Observations: Overholts (1924) reports it from the states named above. Peck (1912) states it is related to Pholiota terrigena Fr. from which he separated it because of its more slender habit, white flesh, adnexed lamellae, and more slender stipe. The dried specimens in the type collection remind one of those of our western form of Pholiota squarrosa more than any other species, but are not as scaly and there is gelatinization of the pileus cuticle. P. penningtoniana differs in the more ovate spores in face view. We regard this species as intermediate between stirps Squarrosoides and stirps Adiposa.