The North American Species of Pholiota
42. Pholiota umbilicata sp. nov.
Illustrations: Text figs. 133-134.
Pileus 2-3 cm latus, campanulato-convexus, umbilicatus, non viscidus, "Sayal brown" deinde "pinkish buff," glaber. Caro concolor; odore et gustu mitis. Lamellae adnatae, "Sayal brown" vel "snuff brown," confertae, marginibus albo-fimbriatae. Stipes 3 cm longus, 2-3 mm crassus, "bistre," flexuosus. Velum faciens fugacem annulum. Sporae 6-8 x 3.5 -4.5 µ, ellipsoideae demum subovoideae, leves, truncatae. Pleurocystidia 16-18 x 4-5 µ, clavata demum ampullacea, pauca. Cheilocystidia 25-35 x 3-5 µ, filamentosa, gracilo-clavata vel ventricosa. Cuticula ex hyphis repentibus composita. Specimen typicum in Herb. Univ. Mich. conservatum est; legit in Pend d'Oreille National Forest, Copeland, Idaho, legit L. E. Wehmeyer, 11 Sept. 1922.
Pileus 2-3 cm broad, campanulate-convex, becoming umbilicate, hygrophanous, not viscid, dull cinnamon ("Sayal brown") moist, fading to pale tan ("pinkish buff") hence hygrophanous, at first margin faintly translucent-striate, glabrous margin tending to remain decurved. Context thin, pliant, concolorous with surface, 2 mm thicker near disc, thinner at margin; odor and taste mild.
Gills broadly adnate, dull cinnamon ("Sayal brown" to "snuff-brown"), narrow, acuminate toward pileus margin, seceding, crowded, edges white fimbriate.
Stipe 3 cm long, 2-3 mm thick, equal, dark yellow-brown ("bister"), darker within, narrowly stuffed, flexuous, slightly tapering, tough to subcartilaginous, pruinose above the apical indistinct evanescent annulus, below the veil-line variegated with white silky fibrils.
Spores 6-7.5 (9) x 4-5 (6.5) µ, ovate to broadly elliptic in face view, obscurely inequilateral in profile, smooth, apex rather broadly truncate from a prominent apical pore, in cross section terete to slightly compressed, pale cinnamon in KOH and ochraceous in Melzer's reagent (paler), wall about 0.3 µ thick.
Basidia 15-20 x 6-7 µ, clavate, 4-spored, hyaline in KOH and Melzer's reagent. Pleurocystidia rare, absent on some sections, 22-26 x 4-8 µ, clavate-rostrate (like 1-spored basidia) to fusoid-ventricose or nearly filamentous, hyaline, thin-walled. Cheilocystidia 25-36 x 4-8 µ, narrowly clavate to fusoid-ventricose or some nearly cylindric, very delicate and difficult to revive. Caulocystidia present above veil-line, similar to the cheilocystidia (subcylindric to clavate or somewhat fusoid-ventricose), thin-walled, delicate and reviving poorly.
Gill trama of subparallel to interwoven non-gelatinous hyphae with thin smooth to slightly roughened walls, the cells 3-8 u, diam., and tubular to somewhat inflated; subhymenium an indistinct narrow nongelatinous zone. Pileus cutis of non-gelatinous hyaline hyphae 3-6 µ diam. and tubular, thin-walled, the layer hyaline-yellowish in KOH; hyphae beneath wider (6-12 µ) and with brownish walls in KOH but no true hypodermium present, the hyphal walls smooth to somewhat incrusted. Context hyphae inflated to 15 µ, thin-walled, hyphae interwoven, yellowish in KOH to hyaline and about the same color in Melzer's reagent. Clamp connections present.
Habit, Habitat, and Distribution: On debris of Thuja plicata, Idaho, September. Type collected at Copeland, Sept. 11, 1922 by C. H. Kauffman and L. E. Wehmeyer.
Observations: This species is known only from the type, and a large part of the material was used up in checking the microscopic characters. It is distinguished by its umbilicate hygrophanous non-viscid pileus, small pleurocystidia, and the delicate cheilocystidia which revive very poorly. It belongs in the P. marginella group since the pileus cutis is not gelatinous, the gills however are narrow as in P. vernalis. Under an oil immersion lens the spores are more obviously truncate than in typical P. vernalis and we suspect that in a spore deposit they will be found to have a redder tone. We feel that this taxon is worth placing on record because its features approach closely certain species of Psilocybe from the Pacific Northwest.