The North American Species of Pholiota

142. Pholiota abruptibulba sp. nov.

Illustrations: Text figs. 302-306.

Pileus (4) 7-9 cm latus, demum late convexus, glutinosus, fulvus. Contextus pallide luteus. Lamellae subdecurrentes, pallide luteae, confertae, latae. Stipes 5-9 cm longus, 10-18 mm crassus, solidus demum cavus, tactu subfulvus, abruptibulbus. Sporae 5.5-7.5 x 3.5-4 µ. Pleurocystidia 50-92 x 10-18 µ. Caulocystidia voluminosa. Specimen typicum in Herb. Univ. Mich. conservatum est; legit prope Larch Mt. Oregon, 30 Oct. 1947. Wm. B. Gruber (Smith 28421).

Pileus (4) 7-9 cm broad, convex with an inrolled margin, becoming broadly expanded with a decurved margin, disc "ochraceous-tawny," or a little darker, "pinkish-buff" on the margin, very glutinous, glabrous except for scattered remains of veil near margin. Context pallid yellowish, thick; odor and taste not distinctive. (Color of flesh after standing becoming near pinkish buff or paler).

Lamellae broadly adnate-subdecurrent, in age short-decurrent, pale yellowish, (near "cartridge-buff"), gradually paler and dull brownish, close to only moderately close, broad, edges soon eroded.

Stipe 5-9 cm long, 10-18 mm thick, equal, solid, becoming hollow, base with a small abrupt bulb, surface whitish or pale yellowish, stained a sordid pale-tawny where handled, slightly fibrillose from a thin, pallid veil.

Spores 5.5-7 (7.5) x 3.5-4 µ, smooth, with a minute pore (under a 1.4 NA obj.), in face view oblong to narrowly elliptic, in profile slightly bean-shaped to nearly oblong, pale cinnamon in KOH, paler and more ochraceous in Melzer's reagent.

Basidia small, 15-20 x 5-6 µ, 4-spored, narrowly clavate, hyaline to yellowish in KOH and Melzer's reagent. Pleurocystidia 50-92 x 10-18 µ, versiform, varying from elliptic-pedicellate (in optical section) to subfusoid to utriform or fusoid-ventricose, with yellowish content at least in the broad neck as revived in KOH and near the apex often with rod-shaped to granular-amorphous bodies irregularly distributed, these bodies apparently soluble in Melzer's reagent, content pale yellowish and homogeneous in Melzer's; the wall thin to slightly thickened (0.5-1 µ) as revived in KOH, but many of them long remaining collapsed, thin-walled as seen in Melzer's sol.; many cystidia are seen to have lateral protrusions or knobs or the cell at times forked. Cheilocystidia 30-50 x 6-12 µ, subfusoid to fusoid-ventricose, thin-walled, content homogeneous and colorless in KOH. Caulocystidia scattered, elongate-clavate, 55-90 (110) x 8-20 (25) µ, thin-walled, content homogenous in KOH.

Gill trama a floccose central strand of parallel to somewhat interwoven hyphae, 4-12 µ broad, the cells short to elongated, thin-walled, yellowish in KOH and smooth, in age the cells considerably inflated; subhymenium a broad gelatinous zone of interwoven, narrow (2-3 µ) smooth hyaline hyphae. Pileus cutis a thick gelatinous pellicle of narrow gelatinizing hyphae 2-5 µ broad and yellow to hyaline in KOH, walls smooth to incrusted and in age very wrinkled; hypodermium of incrusted ochraceous hyphae (in KOH) with the cells not greatly inflated. Context hyphae broad 8-15 µ, yellow in KOH, walls smooth and thin to only slightly thickened. Clamp connections present. All hyphae inamyloid.

Habit, Habitat, and Distribution: Gregarious beside a conifer log, coll. Win. B. Gruber (Smith 28421, type) near Larch Mountain, Oregon. Oct. 30, 1947.

Observations: The distinctive features of this species are the small mostly oblong spores, the very small basidia in relation to the giant pleurocystidia, stipe staining pale tawny where handled, and the abruptly bulbous stipe-base. The pleurocystidia are branched frequently enough to suggest that this will eventually probably also be found to be a distinguishing character. An interesting feature is that apparently the cystidial wall swells somewhat on standing in KOH and appears quite pliant, at least many bent cystidia are seen in mounts as compared to no broken ones.