The North American Species of Pholiota

175. Pholiota piceina (Murr.) comb. nov.

Gymnopilus piceinus Murrill, North Amer. Flora 10: 202. 1917.

Illustrations: Text figs. 387-389; pl. 79a.

Pileus scattered or caespitose, 3-5 cm broad, convex to expanded. obtuse, bright yellow, darker and reddish on the disc, very viscid, glabrous, margin not striate. Context greenish yellow; taste mild.

Lamellae sinuate-decurrent, yellow to pale fuscous, subcrowded, heterophyllus, rather broad, plane.  

Stipe 3-5 cm long, 4-6 mm thick, concolorous but darker at the base, cylindric, somewhat fibrillose, stuffed, becoming hollow.

Spores 7-9 x 4-5 µ smooth, apical pore present but minute; shape in face view oblong to elliptic or slightly ovate, in profile obscurely inequilateral; color in KOH tawny to ochraceous tawny, more ochraceous in Melzer's reagent; wall about 0.25 µ thick.

Basidia 18-24 x 4-6 µ, 4-spored, obese, yellow in KOH and Melzer's reagent. Pleurocystidia 38-66 x 9-12 µ, fusoid-ventricose with obtuse apex, smooth, thin-walled, content ochraceous to pale tawny, fading on standing. Cheilocystidia 27-34 x 7-12 µ fusoid ventricose, apex obtuse, content mostly pale rusty brown to ochraceous; walls smooth or thinly coated with ochraceous material. Caulocystidia at very apex of stipe, similar to cheilocystidia.

Gill trama of a central area of floccose, parallel to interwoven hyphae with elongate cells; walls thin and pale ochraceous in KOH, smooth; subhymenium a thick layer of gelatinous narrow (1.5-3 µ) interwoven branched hyphae hyaline in KOH. Pileus cutis a gelatinous pellicle of hyphae 2-3 µ, ochraceous in KOH and soon collapsing, smooth (as far as observed); hypodermial region of floccose hyphae about like those of context only slightly more ochraceous in KOH, smooth-walled as far as observed. Context hyphae inflated; walls smooth, thin and pale ochraceous. Clamp connections present. All hyphae inamyloid.

Habit, Habitat, and Distribution: On spruce, Maine, August. Type studied.

Observations: The microscopic data are all from the type. The species should be compared carefully with P. graveolens. As dried the gills of the type are about "buckthorn brown" (yellow-brown). The dried pileus is a pale bright yellow. Also, P. vialis and P. piceina should be compared on the basis of additional collections and culture studies if possible. We are not completely satisfied that all three are distinct from each other.

We have notes and a photograph (pl. 71) of an Idaho collection which may belong here:

Pileus 3-6 cm broad, broadly convex becoming nearly plane, with a few faint fibrils from the veil but soon glabrous, color pale bright yellow ("Naphthaline yellow") margin finally decoloring to yellowish white, disc pale orange-brown at maturity, ochraceous at first. Context thickish, yellow, when cut staining a brighter yellow then (finally) dingy brownish; taste mild, odor of corn husks (±), with FeSO4 —olive, with tincture of Guaiac quickly green.

Lamellae pale yellow becoming dull cinnamon brown, broad, adnate, close to subdistant.

Stipe 3-8 cm long, 6-10 mm thick, equal, soon hollow, bright yellow in cortex, surface pale yellow above, soon rusty fulvous below, drying pale bright yellow like the pileus with the basal discoloration not pronounced, thinly fibrillose from the pale yellow veil. Spore deposit dark cinnamon.

Spores 6.5-8 x 3.8-4.2 µ smooth, with a minute apical pore; shape elliptic varying to subovate in face view, nearly elliptic in profile; color in KOH dull cinnamon, paler in Melzer's reagent; wall about 0.25 µ thick.

Basidia 4-spored, 18-24 x 6-8 µ clavate, mostly yellow in KOH (as spores begin to form), dingy ochraceous in Melzer's. Pleurocystidia 50-85 x 9-17 µ fusoid ventricose, apex obtuse, thin-walled, with a long narrow pedicel (originating at edge of central non-gelatinous strand in gill trama), smooth. Cheilocystidia similar to pleurocystidia but shorter, caulocystidia in fascicles, clavate to fusoid-ventricose 30-80 x 10-18 µ, mostly thin-walled and smooth.

Gill trama with a central strand of parallel hyphae of relatively short cells and in area toward the pileus trama the cells inflating markedly, thin-walled, hyaline to yellowish in KOH, some oleiferous hyphae present; subhymenium a gelatinous zone of hyaline branched narrow hyphae. Pileus cutis a pellicle of mixed narrow (2-3 µ) and wider (4 -7 µ) hyphae with disintegrating walls yellowish to hyaline in KOH; hypodermium of interwoven non-gelatinous somewhat roughened to smooth hyphae ochraceous to ochraceous brown in KOH. Context hyphae yellowish to greenish hyaline in KOH, smooth, thin-walled, very compactly arranged. Clamp connections present.

Gregarious on or around old conifer logs, Binarch Creek, Priest Lake, Idaho, Sept. 17, 1966. Smith 73446.

We identify this collection as P. piceina not only because of the dark gills when fresh (we cannot be sure what Murrill meant by "pale fuscous") but especially by the bright yellow color which is preserved in drying. The spores are a shade smaller than in the type but not enough so to appear significant. If Smith 73446 is indeed P. piceina the species is further distinguished by the green Guaiac reaction, the slight peculiar odor, and the cut context becoming brighter yellow and then brownish. The wide hyphae in the gelatinous pellicle may or may not be distinctive. We did not note them in the type, but their apparent absence would not necessarily be critical since several problems arise concerning them—are they stray filaments from the context which gelatinize less than the narrow hyphae, is their presence merely evidence of shreds of the veil too sparse to show macroscopically (they were mostly near the surface) or is the cutis truly "dimitic"—if the latter is the case the character should be regarded as significant.