The North American Species of Pholiota

33. Pholiota aurantioflava sp. nov.

Illustrations: Text figs. 49-50; pl. 11a.

 Pileus 2-4 cm latus, obtuisus demum plano-umbonatus, viscidus, aurantiacus vel aurantiofulvus, squamulosus, glabrescens. Lamellae adnatae, confertae, latae, luteolae, tactu brunneo-maculatae. Stipes 3-5 cm longus, 2-4 mm crassus, deorsum aurantio-brunneus, sursum luteus, fibrillosus. Sporae 6-7.5 x 4-5 µ. Pleurocystidia desunt. Cheilocystidia 26-44 x 3.5-7 µ, ventricoso-rostrata et subcapitata. Specimen typicum in Herb. Univ. Mich. conservatum est; legit prope Nordman, Idaho, 8 Oct. 1956. Smith 54274.

Pileus 2-4 cm broad, obtuse with a curved-in margin, expanding to plano-umbonate or at times margin arched, color between zinc orange and tawny with margin paler and yellowish, viscid, at first spotted with minute squamules above marginal area or over all, glabrescent, slightly striate in age. Context concolorous, pliant; odor and taste not distinctive.

Lamellae adnate, depressed-adnate in age, close, broad, pale yellowish, finally brownish from spores, edges soon serrulate and staining dingy where bruised.

Stipe 3-5 cm long, 2-4 mm thick, equal or nearly so, base soon dingy orange-brown, apex yellowish. Veil pallid and fibrillose, not leaving a distinct zone.

Spores 6-8 x 4-5 µ, smooth, wall slightly thickened, apical pore very minute; in face view elliptic (usually fairly broadly elliptic), in profile elliptic to subelliptic; in KOH dingy ochraceous and with a central refractive globule, wall thin but with a mucilaginous ochraceous thickening against it as revived in KOH, in Melzner's reagent dull tawny (and the mucilaginous material not evident).

Basidia 26-30 x 6-8 µ, 2- and 4-spored, hyaline in KOH, yellowish in Melzer's sol. Pleurocystidia none. Cheilocystidia 26-44 x 3.5-7 µ, ventricose-rostrate, the neck flexuous and 2-3 µ thick, apex subacute to subcapitate, (shape much as in the Galerina sideroides group-almost tibiiform), walls thin smooth and hyaline, content homogeneous. Caulocystidia abundant, versiform: 15-20 x 8-10 µ and clavate, tibiiform and 36-50 x 4-6 x 2-3 x 3.5 µ, and 35-50 x 3-5 µ and nearly setiform, all hyaline in KOH, smooth and with thin-walls.

Gill trama of floccose parallel to subparallel hyphae 4-10 µ, broad and cells inflating even more in age, dull rusty ochraceous in KOH to merely dingy ochraceous, walls smooth and thin; subhymenium gelatinous, of narrow interwoven hyphae. Pileus cutis a very thick gelatinous pellicle of widely separated interwoven hyphae with gelatinous walls, hyphae 2-3 µ diam. and yellowish to hyaline, smooth; hypodermial region of more highly colored (ochraceous) smooth floccose hyphae 4-10 µ diam., and thin-walled. Context hyphae ochraceous in KOH, thin-walled, smooth and cells often much inflated. All hyphae inamyloid. Clamp connections present.

Habit, Habitat, and Distribution: On debris of conifers, Nordman, Idaho, Oct. 8, 1956. Smith 54274, type.

Observations: In the dried condition the pilei are evenly a rather distinct yellow, the disc and margin being the same color. The stipes are browner but have not darkened distinctly in drying as occurs for so many Pholiota species. The stipe tissue in KOH does not darken distinctively. P. aurantioflava is a most unusual species in that the basidiocarps when fresh resemble those of subgenus Flammula in both appearance in the field and in the combination of moderately dextrinoid spores and lack of pleurocystidia. The gelatinous subhymenium and cheilocystidia connect to stirps Sideroides of Galerina. It appears that the more Galerina and Pholiota are studied the more intermediates we find. This situation is of importance in evaluating the families of rusty brown and purple-brown spored agarics. Because of such intermediate species as this the connection from Galerina to Pholiota subg. Flammula is solidly established, for here the aspect of the basidiocarp is clearly with a group of Pholiotae lacking pleurocystidia, but the microscopic features of subhymenium still indicate the stirps Sideroides of Galerina.