The North American Species of Pholiota

78. Pholiota pusilla (Pk.) comb. nov.

Flammula pusilla Peck, New York State Mus. Bull. 67: 26. 1903.

Illustration: Peck, N.Y. Mus. Bull. 67, pl. M., Figs. 35-41. Text figs. 102-104; 105-106.

Pileus 1.2-2.5 (3.5) cm broad, convex becoming nearly plane, pale buff or yellow-ferruginous, slightly viscid, glabrous. Context thin.

Lamellae adnate, whitish when young, brownish-ferruginous when mature, narrow, crowded.

Stipe 1.5-3 cm long, 2 mm thick, whitish, becoming ferruginous toward the slightly villose-strigose base, apex flocculent-pulverulent, equal, solid or stuffed. Veil slight, whitish to pale yellow.

Spores 6-7.5 x 3.5-4 µ, smooth, apical pore very minute but present; shape in face view oblong to narrowly elliptic, in profile slightly bean-shaped to suboblong, as revived in KOH rusty brown, merely ochraceous in Melzer's reagent; wall about 0.25 µ thick.

Basidia 17-23 x 4.5-6 µ, 4-spored (rarely 2-spored), subclavate hyaline in KOH, yellowish in Melzer's reagent. Pleurocystidia abundant, 26-35 x 10-20 µ, broadly fusoid to clavate-mucronate, with bright yellow coagulated content that adheres along wall preventing the cell from reviving in KOH, content orange to dull red in Melzer's reagent. Cheilocystidia 18-32 x 4-8 (9) µ, cylindric-capitate to narrowly fusoid-ventricose, walls thin, smooth and hyaline, content homogeneous, hyaline to yellowish. Caulocystidia 27-46 x 6-12 µ elongate clavate to fusoid-ventricose or irregularly fusoid, walls yellowish and often thickened slightly (0.5) µ, content a coagulated more or less wrinkled mass of amorphous material pale yellow to orange-brown in KOH, also cells similar to cheilocystidia at very apex.

Gill trama of a central area of floccose hyphae of elongate celled hyphae with smooth thin yellowish walls in KOH, cells (4) 5-12 µ diam. (more inflated in center area), subhymenium a broad and distinct gelatinous layer. Pileus cutis a collapsed trichodermium of nongelatinous loosely arranged rusty brown hyphae with encrusted walls, (usually heavily banded), the hyphae 4-9 µ wide and cells not greatly inflated; hypodermial zone bright rusty in KOH fading to ochraceous, almost pseudoparenchymatic in structure (cells inflated and closely packed), cell walls thickened (double) to about 0.5 µ. Context hyphae with walls like those of hypodermial area-refractive, smooth and showing a middle layer. Clamp connections present. All hyphae inamyloid.

Habit, Habitat, and Distribution: On roots, stumps and water-soaked wood in open places, Smithtown, Suffolk Co., New York. Type studied.

Observations: Kauffman in his study of the type noted the curious cells in the hymenium, which in the light of the present work are merely cystidia approaching the chrysocystidia type. Harding placed the species in synonomy with Flammula carbonaria, probably because Kauffman placed it in synonymy with F. highlandensis, and in an examination of a portion of the type Hesler found no pleurocystidia. Smith's observations were made on the specimens showing the tawny mycelium around the base (the appearance is like that of Xeromphalina) and his observations check with Kauffman's on microscopic features. Hence we interpret the species as having chrysocystidial-like cells in the hymenium. Kauffman thought the peculiar cells were foreign and reduced the species to synonymy with F. highlandensis from which it is readily distinct by obvious characters. The question of the viscidity of the pileus, a character mentioned by Peck, is more difficult to explain. The only explanation we can offer here is that the epicuticular hyphae in spite of being incrusted buckle and collapse as if the wall were very weak—much as in some other species known to be viscid to the touch. Hence Peck's observation, as usual, was undoubtedly an accurate one. The point is that the anatomical study shows the layer is not a gelatinous pellicle as in P. highlandensis. Flammula ascophora Pk may be a synonym of this species.

Because of the situation in regard to the type, our account here is based entirely on the original account of Peck and a study of specimens with the tawny mycelium at the base of the stipe. One is most apt to confuse this species in the field with Pholiota vernalis. P. prolixa is very slimy when fresh and wet.