The North American Species of Crepidotus

83. Crepidotus maximus sp. nov.

Crepidotus mollis sensu Sm. & Hes., Elisha Mitchell Sci. Soc. Jour. 56: 310. 1940.
[Non C. mollis (Fr.) Staude]

Illustrations: Figs. 23, 156.

Pileus 4-13 cm latus, sessilis, imbricatus, dimidiatus, cuneatus velflabelliformis, convexus deinde planus, albus vel albidus, denique "light ochraceous buff," rivulosoreticulatus,fibrillosus, viscidus demum glutinosus, necnon incurvatus. Lamellae albae deinde "snuff brown,"purpureo-brunneae confusae, confertae, angustae. Sporae (6) 7-8 (9) x 4-4.5 (5) µ, ellipsoideae, planae. Basidia 23-30 x 5-7 µ di- et tetraspora. Pleurocystidia desunt; cheilocystidia 48-96 x 5-10 µ. Cuticula gelatinosa, hyphas erectas sine colore gerens, 3-5 µ latas. Fibulae adsunt. Specimen typicum in Herb. Univ. Tenn.; lectum prope Knoxville, Tenn., L. R. Hesler 9718.

Pileus 4-13 cm broad, sessile, somewhat imbricate, dimidiate, cuneate or broadly flabelliform, convex, then more or less plane, or the margin wavy and the midportion more or less depressed, white or whitish, becoming tinted "light ochraceous-buff," coarsely rivulose-reticulated, innately fibrillose, distinctly viscid or almost glutinous when wet, soon dry, not hygrophanous, margin incurved and even. Context thick, tough, rather turgid, pallid. Lamellae radiating, white at first, becoming "snuff brown," "argus brown," or "Brussel's brown," with a purple-brown tint where bruised, close, linear, relatively narrow (up to 5 mm), narrowed at the ends, edges white-fimbriate, at times gelatinous.

Stipe none, pileus tapering into a stipe-like base, which is usually white villose-strigose.

Spores (6) 7-8 (9) x 4-4.5 (5) µ, ellipsoid in front view, shorter spores slightly inequilateral in profile, some spores suboblong, 7.5-8.5 x 4 µ, smooth, "Prout's brown" in deposits, brown in 2% KOH. Basidia 23-30 x 5-7 µ, 2-4-spored. Pleurocystidia none; cheilocystidia 48-96 x 5-10 µ, long clavate-cylindric, at times short-clavate, occasionally subcapitate, sometimes pale fuscous, many of tramal origin. Gill trama with a broad mediostrate of parallel to subparallel, dark hyphae, the hyphae on either side colorless and loosely interwoven. Subhymenium of narrow, more or less interwoven hyphae. Pileus trama interwoven, hyphae 5-12 µ broad. Cuticle a broad (350 -500 µ or more) zone of gelatinous, interwoven, narrow (2-3 µ) hyphae, the surface usually bearing numerous colorless, narrow (3-5 µ) hyphae forming a trichodermium. Hypodermium usually quite distinct. Clamp connections present on the hyphae of the epicutis, pileus trama, and the gill trama.

Habit, Habitat, and Distribution: On dead, standing hickory trunk, Tennessee, November.

Material Studied: TENNESSEE: Hesler 9718, type, from near Knoxville, in Knox County, Nov. 7, 1936.

Observations: This was erroneously identified by us as C. mollis (Smith & Hesler, 1940), but it differs from the latter in the presence of clamp connections, more narrow spores, color-change of gills when bruised, and the lack of brown, incrusted hyphae.