The North American Species of Pholiota

166. Pholiota tetonensis sp. nov.

Illustrations: Text figs. 364; 365-366.

Pileus 1-2.5 cm latus, convexus vel conicus, demum acute umbonatus, laete luteus ("deep chrome"), glaber. Lamellae adnatae, demum subdistantes, latae, luteae. Stipes 1.5-4 cm longus, 2-4 mm crassus, sursum pallide luteus, deorsum demum subfulvus, luteo fibrillosus. Sporae 7-9 x 4-5 µ. Pleurocystidia 40-70 x 10-22 µ, late ventricosa vel subfusoidea; tenuitunicata. Specimen typicum legit prope Jackson Lake, Wyoming, 29 June 1955, W. G. Solheim 3763, in Herb. Univ. Mich. conservatum est.

Pileus 1-2.5 cm broad, convex or conic, strongly and acutely umbonate, "deep chrome," center slightly darker, margin paler, glabrous. Context yellowish; odor and taste fungoid.

Lamellae adnate, yellowish at first, then yellowish brown, nearly subdistant, medium broad.

Stipe 1.5-4 cm long, 2-4 mm thick, pale yellow above, darker below, flesh yellowish, with scattered veil fibrils. Veil yellow, fibrillose.

Spores dull cinnamon ("Sayal-brown") in deposits; 7-9 x 4-5 µ, smooth, apical pore distinct but apex not truncate, wall dull cinnamon in KOH, in Melzer's reagent paler and more ochraceous, in face view oblong to elliptic, rarely ovate, in profile subelliptic to obscurely inequilateral, wall about 0.3 µ thick.

Basidia 25-28 x 6-8 µ, 4-spored, clavate, hyaline to yellow in either KOH or Melzer's reagent. Pleurocystidia 40-70 x 10-22 µ, abundant, broadly fusoid ventricose to broadly subfusoid varying to broadly elliptic-pedicellate, walls thin and most cells remaining collapsed (in KOH), smooth, content amber-brown to dark ochraceous in neck, more homogeneous and paler in ventricose part, colored content tending to be reticulate folded or otherwise irregular in outline as seen on revived material under microscope, apex broadly rounded to obtuse and smooth. Cheilocystidia similar to pleurocystidia but on the average shorter and more obese. Caulocystidia none or a few clavate hyphal end-cells present.

Gill trama with a hyaline to yellowish central strand of parallel to subparallel hyphae with thin hyaline to yellowish smooth non-gelatinous walls and short to elongate cells 4-12 µ broad, some rusty ochraceous oleiferous hyphae present; subhymenium a narrow (2-3 µ), gelatinous zone of hyaline smooth interwoven hyphae. Pileus cutis a gelatinous pellicle of appressed-interwoven hyphae 3-5 µ diam. more or less ochraceous in KOH, and smooth to incrusted; hypodermium of more rusty-orange floccose hyphae 4-10 µ diam. with incrusted walls. Context hyphae with inflated cells, thin-walled, smooth to (rarely) incrusted, walls ochraceous in KOH; some large worm-like oleiferous hyphae present and rusty brown in KOH. Clamp connections present. All hyphae inamyloid.

Habit, Habitat, and Distribution: On rotting wood, Wyoming, Grand Teton National Park, June 29, 1955. Solheim 3763, type.

Observations: This species is very similar to P. acutoconica var. acutoconica, but is at once distinguished by its more obese pleuro- and cheilocystidia, and deep chrome colored pileus. The more distant gills are a possible additional difference but more collections are needed to substantiate this. It is very likely that there is a difference in the color of the spore deposit, but again more data are needed on the character. When found it is likely to be mistaken for one of the P. alnicola group.