The North American Species of Pholiota

50. Pholiota pallida sp. nov.

Illustrations: Text figs. 149-150; pl. 18a.

Pileus 10-15 mm latus, plano-convexus, deinde depressus, glabrosus, viscidus, pallido-coriaceus; odore et gustu mitis. Lamellae adnexae, concolores, confertae, angustae, marginibus planae. Stipes 3-4 cm longus, 2-3 mm crassus, concolor, basis distorta. Velum tenue. Sporae 6-7.5 x 3.5-4.5 µ, ellipsoideae vel ovoideae, truncatae, leves. Pleurocystidia desunt; cheilocystidia 33-46 x 5-10 µ, clavato-capitata, obclavata, ampullacea, apicibus nonnumquam furcata vel ramosa. Cuticula gelatinosa. Caulocystidia 27-54 x 6-13 µ, clavata, fusoidea, ventricosa. Specimen typicum in Herb. Univ. Mich.; lectum prope Payette Lakes, Idaho, 3 Aug., 1964. Smith 68837.

Pileus 10-15 mm broad, plano-convex with the margin incurved, expanding to shallowly depressed and with an arched margin, surface glabrous, thinly viscid, color watery cream color (about like pale butter scotch), evenly colored, when dried pale yellow to whitish. Context thin, pallid, odor and taste not distinctive, KOH and FeSO4 both negative.

Lamellae close, narrow to moderately broad, adnexed, pale cream color becoming rusty brown as spores mature, edges even, concolorous with faces in young stages.

Stipe 3-4 cm long, 1.5-3 mm at apex, 3-6 mm at base, concolorous with young pileus throughout, not discoloring in age or on drying, with an inconspicuous fibrillose zone left where veil breaks, nearly naked downward to the white tomentose base, variously crooked and twisted downward, apex fibrillose-punctate.

Spores 6-7.5 x 3.5-4.5 µ, elliptic to ovate in face view, subelliptic to obscurely inequilateral in profile, smooth, tawny in KOH, and slightly darker in Melzer's reagent; wall thickened to about 0.25 µ (estimated) thick, apex obscurely to distinctly truncate from an apical pore. Basidia 4-spored 16-21 x 5-6 µ, narrowly clavate, hyaline in KOH, yellowish in Melzer's reagent. Pleurocystidia none. Cheilocystidia scattered, 33-46 x 6-10 µ subcylindric to obscurely fusoid-ventricose (tapered to an obtuse or rounded apex from a slightly ventricose base), hyaline, thin-walled, rarely with 1-2 protuberances around apex. Caulocystidia 4-7 µ diam., length variable (20-50 µ long), filamentous to narrowly clavate; stipe tissue not darkening in KOH.

Gill trama of hyphae parallel to subparallel the cells becoming inflated to 12 µ or more in age and relatively short; subhymenium indistinct, hyphal walls thin, hyaline to pale yellowish in KOH and not much change in Melzer's reagent (in-amyloid). Pileus cutis a moderately thick layer (3-8 hyphae) of hyaline subgelatinous tubular thin-walled hyphae with smooth walls; hypodermial region of wider hyphae the walls thin and yellowish to hyaline in KOH and orange ochraceous in Melzer's reagent. Context hyphae about like hypodermial hyphae. Clamp connections present.

Habit, Habitat, and Distribution: On a conifer log, caespitose; Lake Fork Creek, Payette Lakes, Idaho, Aug. 3, 1964. Smith 68837, type.

Observations: This species is unusual in that the hyphae of the stipe do not become dark in KOH. The over-all pale color is also distinctive in relation to the others of the stirps Vernalis. It is somewhat intermediate between stirps Vernalis and stirps Marginella in the features of the gills and pileus cutis.