The North American Species of Pholiota

89. Pholiota oregonensis Murrill, Mycologia 4: 262. 1912.

Hypodendrum oregonense Murrill, Mycologia 4: 262. 1912.

Illustrations: Text fig. 181.

Pileus 5 cm or broader when mature, convex, obtuse, ochraceous-buff to ochraceous-tawny, glabrous, dry, margin strongly incurved. Context thin, cremeous; taste nutty or amygdaline in dried specimens.

Lamellae adnate, yellow or yellowish brown, becoming darker, medium-distant to distant, strongly interveined.

Stipe 6-10 cm long, 8-20 mm thick, yellowish above, fulvous below, with small, scattered, unicolorous, subfloccose, evanescent scales pointing upward, terete or compressed, equal or enlarged upward or downward, solid. Veil forming a superior or nearly apical, irregular, yellowish white annulus.

Spores 7.5-10 x 4-5 (6) µ, smooth, germ pore very minute; shape in face view more or less distinctly ovate, in profile inequilateral to obscurely so; color in KOH dull cinnamon, in Melzer's reagent dark reddish tawny (dextrinoid).

Basidia 25-34 x 5-7.5 µ, narrowly clavate, usually with a long narrow (2-3 µ) pedicel, 4-spored, hyaline to yellowish in KOH and Melzer's reagent. Pleurocystidia none. Cheilocystidia 23-33 x 3-9 µ, cylindric-flexuous to more or less clavate, hyaline, thin-walled, content not distinctive. Caulocystidia present as clavate end-cells of filamentous hyphae, not distinctive.

Gill trama of interwoven refractive hyphae with cinnabar to orange-yellow content in Melzer's reagent, "colloidal" in KOH, walls thin and smooth; subhymenium of narrow interwoven somewhat gelatinous hyphae. Pileus cuticle a well defined layer of subgelatinous refractive narrow hyphae 2-3 µ diam. hyaline to yellowish in KOH and Melzer's reagent; hypodermial region of ochraceous hyphae with colloidal-appearing content as revived in KOH, in Melzer's this layer and context hyphae with cinnabar to ochraceous or orange content. Clamp connections present.

Habit, Habitat, and Distribution: On a living willow, Oregon, November. Known from the type (Murrill, 754).

Observations: This species is likely to be mistaken in the field for Gymnopilus spectabilis but the latter is easily distinguished in the laboratory by the rough spores. Overholts (1928) pointed out the similarity. The dextrinoid spores, bright colors and lack of pleurocystidia place the species immediately in stirps Alnicola. The pleurocystidia observed by Overholts were more than likely immature basidia. The same situation as regards viscidity that applies to P. flammans and P. alnicola also applies here. The cuticle has all the features of one which becomes a gelatinous pellicle in wet weather. For the time being at least we recognize both P. malicola var. macropoda and P. oregonensis. Both fruit in large clusters and both tend to have greatly enlarged stipes. In P. malicola var. macropoda the substrate is conifer wood whereas in P. oregonensis it is willow. This may not be significant taxonomically. P. oregonensis has distant gills and a scaly stipe with the scales pointing upward. We have not seen this in P. malicola var. macropoda. In the latter the pileus colors are apparently brighter, a faint though distinct odor is present when specimens are fresh, and the gills are typically close.