The North American Species of Pholiota

8. Pholiota subsulphurea sp. nov.

Illustrations: Text figs. 5-6.

Pileus 10-15 mm latus, convexus, siccus, demum subsquamulosus flavus. Contextus luteus, amarus. Lamellae subdistantes, latae, adnatae, subsulphureae. Stipes 2.5-3 cm longus, 2.5-3 mm crassus subsulphureus, deorsum fulvus, vellum lutelum. Sporae 6.5-7.5 x 4-4.5 µ, leves. Pleurocystidia desunt. Cheilocystidia 28-64 x 6-10 µ, filamentoso-capitata. Specimen typicum in Herb. Univ. Mich. conservatum est; legit prope Tahquamenon Falls, Mich. 29 June 1953 Smith 41356.

Pileus 10-15 mm broad, convex with an incurved margin, becoming plane or nearly so, surface dry and matted-fibrillose, becoming somewhat areolate to diffracted squamulose; color bright yellow (rich sulphur-yellow), in age near orange-yellow; margin at first appendiculate from veil remnants. Context yellow but readily staining rusty, cutis quickly rusty brown in KOH (NH40H reaction weaker), odor none, taste very bitter. Lamellae close becoming subdistant, horizontal, adnate, moderately broad, sulphur-yellow young, near tawny mature, edges flocculose.

Stipe 2.5-3 cm long, 2.5-3 mm thick, equal, bright yellow, floccose-squamulose to the annular zone, pruinose above, staining rusty brown from base up or where handled or where in contact with bases such as KOH. Veil fibrillose, yellow.

Spores 6.5-7.5 x 4-4.5 (9 x 3.5) µ smooth, lacking an apical pore, tawny in KOH, in Melzer's reagent merely yellowish; shape in face view elliptic to oblong, in profile slightly bean-shaped.

Basidia 4-spored, 18-23 x 4.5-6 µ, narrowly clavate, yellow to clay-color in KOH (many sporulating basidia with dark rusty brown content seen). Pleurocystidia none. Cheilocystidia abundant, flexuous-capitate as in P. erinaceella, 28-46 x 6-10 µ, bright yellow in KOH, thin-walled, smooth, wall hyaline. Caulocystidia 30-60 x 8-14 µ, in shape similar to cheilocystidia but head broader and often flattened, yellow to orange in KOH.

Gill trama of subparallel to interwoven thin-walled hyphae bright yellow in KOH, oleiferous hyphae orange-yellow; subhymenium not distinctive (very narrow and not gelatinous). Pileus cuticle a tangle of hyphae 5-14 µ diam., the cells tubular to somewhat inflated but typically more than 4 times longer than broad, pale tawny to pale cinnamon in KOH, thin-walled, walls smooth to minutely roughened; terminal cells somewhat cystidioid. Clamp connections present. All tissues inamyloid.

Habit, Habitat, and Distribution: Clustered on a log of Fagus, Tahquamenon Falls State Park, Mich. June 29, 1953, Smith 41356 (type), and from Oakland County, Smith 73247, 73269.

Observations: This species is close to P. curvipes but it at once distinguished in the field by the very bitter taste. From P. multifolia which has a bitter taste, it differs in broad subdistant gills at maturity and by having numerous caulocystidia over the tipper half of the stipe. We seldom find P. curvipes caespitose. We assume that P. fagicola is not bitter. It is described as having distant arcuate gills.