The North American Species of Crepidotus

79. Crepidotus fusisporus var. fusiporus sp. nov.

Illustration: Fig. 152.

Pileus 6-20 mm latus, conchatus demum dimidiatus, albus, villosus vel fibrillosus, margine crenatus vel undulatus, involutus. Lamellae albae deindefusco-luteolae, denique "clay color," medio-latae, subdistantes. Sporae 7-9.5 x 3.5-4.5 (5.3) µ, fusoideae, punctatae vel paene planae. Basidia 24-32 x 5-7 µ, tetraspora. Pleurocystidia desunt; cheilocystidia 20-40 x 4-5 µ. Cuticula ex hyphis repentibus composita, hyphas erectas sine colore gerens, 3-4 µ, latas. Fibulae adsunt. Specimen typicum in Herb. Univ. Mich.; lectum Tahquamenon Falls State Park, Mich., July 2, 1955, A. H. Smith 49680.

Pileus 6-20 mm broad, sessile, conchate to dimidiate, margin long remaining inrolled, surface snow white, dry, villose or fibrillose, margin crenate to wavy in age. Context soft, white; odor and taste not distinctive.

Lamellae medium broad, subdistant or nearly so, broadly adnate to decurrent, white, becoming dingy yellowish and finally pale clay color, edges even. Stipe wanting or short, white and finely tomentose, obsolete.

Spores 7-9.5 x 3.5-4.5 (5.3) µ, fusoid, inequilateral in profile, nearly smooth or obscurely punctate, very pale yellowish in 2% KOH, tending to hang together in groups of 2, 3, or 4, color in thin deposit: yellowish. Basidia 24-32 x 5-7 µ, 4-spored. Pleurocystidia none; cheilocystidia 20-40 x 4-5 µ, cylindric, clavate, to subventricose. Gill trama interwoven, hyphae 5-8 µ broad. Pileus trama interwoven. Cuticle of repent hyphae bearing a turf of long hyphae, 3-4 µ broad, colorless, branched. Clamp connections on the hyphae of the pileus trama and the epicutis.

Habit, Habitat, and Distribution: On hardwood sticks, dead branches, and logs, Maine, New Hampshire, Michigan, and Washington, June-August.

Material Studied: MAINE: Bigelow 1956 (MICH), 10194 (MASS); Thiers 3903 (MICH); MICHIGAN: Beach 4, 5, 6 (MICH); Smith 49680 (type, on hardwood twigs, Tahquamenon Falls State Park, July 2, 1955), 49684, 49685, 49686, 49687; Thiers 2849 (MICH); NEW HAMPSHIRE: Miller 423 (MICH); WASHINGTON: Smith 29213.

Observations: From our study of some forty collections of C.fusisporus, it is apparent that this is a complex of varieties. The variations in form of the cheilocystidia and of the epicuticular hyphae were at the outset puzzling. So far as our studies now have gone, these variations, from collection to collection, are sufficiently stable to assign populations to varietal status. These varieties are united through their fusoid spores. The spores also vary somewhat in their surface character: they may be distinctly punctate to obscurely so, or smooth to nearly so. A microscopic mount showing apparently smooth spores will also show some spores which are obscurely punctate. Thus, this character, in our experience, seems hardly reliable for distinguishing the varieties.