The North American Species of Pholiota

73. Pholiota burkei sp. nov.

Illustrations: Text figs. 65-66.

Pileus 3-5 cm latus, convexus demum late convexus, saepe obtuse umbonatus, hygrophanus, melleus, ad marginem olivaceus, glaber, striatulatus. Lamellae sinuatae, luteolae, angustae, confertae. Stipes 3-5 cm longus, 4-9 mm crassus, sursum pallide luteus; deorsum fibrillosus vel squamulosus et demum subfulvus. Sporae 5.5-7 (7-9) x 3.5-4 (4.5-5) µ, ovatae. Pleurocystidia 25-40 x 6-9 (12) µ, ellipsoideo-mucronata vel ventricoso-rostrata. Caulocystidia 24-42 x 3-6 µ, cylindricato-capitata. Specimen typicum in Herb. Univ. Mich. conservatum est; legit prope Montgomery, Ala., R. P. Burke (AS) 29 Sept. 1942.

Pileus 3-5 cm broad, convex, expanding plane, at times with a low umbo, hygrophanous, when moist the central portion "honey-yellow," outer portion near "ecru-olive," when faded "deep colonial-buff," paler on the marginal portion, at times striatulate, glabrous, viscid. Context cream-color, unchanging; odor and taste mild.

Lamellae sinuate with a decurrent tooth, near "colonial buff" when young, becoming "honey-yellow" then "buckthorn-brown," five tiers of lamellulae present, narrow to moderately broad, close.

Stipe 3-5 cm long, 4-9 mm thick, apex "massicot-yellow" or paler, glabrous over the upper two-thirds, coarsely fibrillose-squamulose below, squamules reflexed, finally "buckthorn-brown," equal to enlarged above, at times compressed. Veil pallid, at first submembranous, finally subarachnoid, leaving a fringe on the pileus margin and an evanescent zone on the pileus.

Spores 5.5-7 (7-9) x 3.5-4 (4.5-5) µ, ovate to elliptic in face view, more or less inequilateral in profile, smooth, apical pore evident on all, on larger spores apex truncate (N.A. 1.4 lens), dull tawny in KOH, paler (ochraceous) in Melzer's sol. wall moderately thick ± 0.3 µ).

Basidia 17-21 (20-25) x 4.5-6 (6-7.5) µ, 4-spored rarely 2-spored (only small ones were observed to be 2-spored), hyaline in KOH, yellowish in Melzer's reagent. Pleurocystidia scattered to rare, 25-40 x 6-9 (12) µ, two types observed; 1) elliptic-mucronate with thin hyaline walls and homogeneous content and 2) fusoid-ventricose to ventricose-elongate (neck filamentose), with a highly refractive amorphous body in ventricose part as revived in KOH, walls thin, smooth and hyaline, neck often drawn out into a filamentose extension, with walls flexuous. Caulocystidia rather numerous, 24-42 x 3-6 µ filamentose-subcapitate to narrowly fusoid-ventricose, apex subcapitate to acute, walls thin and hyaline, content homogeneous.

Gill trama a central area of subparallel hyphae, 6-15 µ broad (cells inflated in age), walls thin smooth and hyaline to yellowish in KOH, content homogeneous in KOH; subhymenium of narrow subparallel gelatinous colorless hyphae. Pileus cutis a thick gelatinous layer of narrow interwoven hyphae 2-3 µ diam., yellowish in KOH and walls smooth to asperulate (in age); hypodermium of ochraceous smooth-walled floccose hyphae 4-10 µ diam. Context hyphae 8-18 µ or more thick, (cells greatly inflated) walls smooth, thin colorless to yellowish in KOH; oleiferous hyphae present, yellow in KOH. All hyphae inamyloid. Clamp connections present.

Habit, Habitat, and Distribution: Caespitose on bare soil, in a road through a swamp, Alabama, collected by R. P. Burke (A.S.) Sept. 29, 1942.

Observations: This is a curious species in nearly all respects. The yellow colors, hygrophanous context, yellow gills and stipe when young, and scales at the stipe base make it a distinctive species in the field. Microscopically the tendency of the chrysocystidia to have a long filamentose neck is most unusual for this type of cystidium. The large spores are borne in 4's on the large basidia. No spores attached to two-spored basidia were seen. We are certain, however, that not all of the large spores seen are from 4-spored basidia. The fact that these larger spores in a fair number of individuals have a truncate apex is one reason for de-emphasizing the feature as a generic character.