North American species of Mycena.

EUMYCENA: ADONIDAE

153

65. MYCENA OLIDA var. americana, var. nov.
Illustrations:
Plates 11 C, 18 B; Text figs. 13, nos. 6-10 (p. 148); 14, nos. 1-4 (twospored form) (p. 154).
Beardslee and Coker, Journ. Elisha Mitchell Sci. Soc., 40, pl. 15 (lower
right).
Pileus 3-20 mm. latus, obtuse conicus demum campanulatus,
impolitus, glabrescens, striatus, lacteo-albus; sapor mitis; lamellae
adnatae, confertae vel distantes, latae, albidae; stipes 1-8 cm. longus,
1-2 mm. crassus, deorsum strigosus, sursum dense pruinosus, albidus;
sporae 7-8 X 3.5-4.5 t,; pleurocystidia 34-68 X 8-16 A, subcylindrica
vel fusoide ventricosa, levia; cheilocystidia 26-42 X 8-12 p. Specimen typicum in Herb. Univ. Mich. conservatum. Legit A. H. Smith,
n. 15244, prope Dexter, Mich., Sept. 2, 1940.
Pileus 3-20 mm. broad, obtusely conic with the margin straight
at first, becoming broadly conic, campanulate or nearly plane with a
wavy or scalloped margin in age, sometimes merely convex and becoming plane, surface pruinose-pubescent at first (under a lens) but
soon glabrous and polished, lubricous when moist, hygrophanous,
striate to the disc before fading, pure white to milky white and soon
sordid creamy yellowish over the disc, often becoming pale tan in age;
flesh thin but quite tough and cartilaginous, white or becoming
yellowish in age, no odor, taste mild or slightly farinaceous; lamellae
ascending-adnate to uncinate, close (large specimens) to distant
(small individuals), moderately broad and somewhat ventricose,
white but becoming creamy yellowish, edges even and whitish; stipe
1-8 cm. long, (0.5) 1-2 mm. thick, equal or tapered below, base often
rooting in the debris and densely strigose over the lower portion,
upper part densely pruinose at first but soon glabrous and polished,
white, sometimes becoming yellowish or sordid tan in age.
Spores 7-8 X 3.5-4.5,u, ellipsoid, smooth, hyaline, apiculus rather
prominent, spores from two-spored basidia 7-8.5 X (5) 6-7.5, and
broadly ellipsoid to globose, yellowish in iodine; basidia usually fourspored, two-spored forms rare; pleurocystidia rare to scattered, 34-68
X 8-16 J; gill trama homogeneous, yellowish in iodine; pileus trama
with a pseudoparenchymatous layer of enlarged cells covering the
surface, the remainder filamentous, yellowish in iodine, surface
hyphae at first with a rather dense covering of upright pilocystidia or