The North American Species of Crepidotus
92. Crepidotus variabilis var. variabilis (Fr.) Kummer, Der Führer in die Pilzk., p. 74. 1871.
Agaricus variabilis Fr., Syst. Myc. 1: 275. 1821.
Agaricus (Crepidotus) cheimonophyllus B. & Br. apud Berk. Outlines, p. 164. 1860.
Claudopus variabilis (Fr.) Gill., Champ. Fr., p. 426. 1876.
Dochmiopus variabilis (Fr.) Pat., Hymen. Europe, p. 113. 1887.
Crepidotus cheimonophyllus (B. & Br.) Sacc., sensu Sydow, Syll. Fung. 5: 882. 1887.
Illustration: Fig. 164.
Pileus 4-20 mm broad, resupinate to reflexed, attached laterally or dorsally, flabelliform, dimidiate or reniform, white, villose or tomentose, dry. Context moderately thin.
Lamellae radiating from a lateral point, white then ocher-flesh to pinkish-cinnamon, close or subdistant, medium broad, edges fimbriate.
Stipe none, or present when young and then very short, eccentric, and temporary.
Spores 4.5-6 x 2.5-3.5 (4) µ, oblong-ellipsoid, at times subovoid, punctate, pale brownish. Basidia 20-28 x 5-6 µ, 2-4-spored. Pleurocystidia none; cheilocystidia (18) 20-50 x 5-16 µ, clavate, ventricose, at times capitate, occasionally forked or branched, more rarely subcuneate. Gill trama interwoven, hyphae 3-7 µ broad. Pileus trama interwoven. Cuticle of repent hyphae, bearing a turf of hyphae 3-4 µ broad, colorless, densely tangled, those on the margin at times flexuous. Clamp connections present.
Habit, Habitat, and Distribution: On hardwood, Michigan; England and Netherlands, July-October.
Material Studied: MICHIGAN: Smith 66824; ENGLAND: Smith 63231 (MICH); Wakefield 8-10-36 (K); 4-11-45 (K); Dennis 30-9-51 (K); Reid (TENN 24024); NETHERLANDS: Bas (TENN 26105).
Observations: The collections we have studied seem to exhibit some variations in spore-width, and in the form of the cheilocystidia. Those which have spores up to 2.5-4 µ broad, and regularly shaped cheilocystidia, we interpret as C. variabilis var. variabilis; those with relatively broader spores (4-5 µ), we refer to variabilis var. subsphaerosporus; and, finally, those with typical spores (2.5-4 µ broad), but with filamentous, often flexuous and branched cheilocystidia, we refer to variabilis var. trichocystis.