The North American Species of Crepidotus

56. Crepidotus subnidulans (Overh.) comb. nov.

Claudopus subnidulans Overh., Ann. Mo. Bot. Garden 3: 195. 1916.
Phyllotopsis subnidulans (Overh.) Sing., Agaricales (Lilloa 22: 264). 1951.

Illustrations: Figs. 117, 118.

Pileus 0.5-2 cm broad, sessile, reniform or dimidiate, convex, dry, fibrillose-tomentose, bright orange-tawny, margin inrolled, even or slightly striate. Context thin, white; odor and taste none.

Lamellae radiating from the point of attachment, subdistant, rather broad (3-5 mm), salmon-colored or dull orange.

Stipe none, pileus attached by a white, tomentose base.

Spores 5.5-7.5 x 5-7 µ, globose to slightly subglobose, smooth, pale brown in 2% KOH. Basidia 35-41 x 10-13 µ, 2-4-spored, basidia clavate, the lower two-thirds slender. Pleurocystidia 43-53 x 3.5-6 µ, cylindric to subclavate, rare; cheilocystidia 38-50 x 8-13 µ, pale fuscous, clavate or bottle-shaped, apparently of tramal origin, rare. Gill trama undulating subparallel. Pileus trama radial, appearing as pseudoparenchyma in tangential sections. Cuticle of repent hyphae, bearing rather numerous, more or less erect, fuscous, septate, rarely branched hyphae, the terminal elements cystidioid (pileocystidia ). Clamp connections moderately common in the epicuticular hyphae. Lactifers none.

Habit, Habitat, and Distribution: On rotten log, Missouri, October.

Material Studied: MISSOURI: Overholts 13045, the type (BPI), from Jefferson Barracks, near St. Louis, Oct. 25, 1913.

Observations: Singer (1951) doubtfully assigns this to the genus Phyllotopsis. That genus, however, has cylindric-allantoid spores. Under modern systems, Claudopus has pink, angular spores, and is usually placed in Rhodophyllus. The difficulty in placing subnidulans in Crepidotus is its salmon-pink spores (in deposits). They are, however, pale brownish in 2% KOH, under the microscope. Pending additional collections and observations, we are placing it in Crepidotus. The description of microscopic characters above is based on a study of the type.