North American species of Mycena.

384 NORTH AMERICAN SPECIES OF MYCENA

192. MYCENA KAUFFMANII Smith
Mycologia, 27: 588. 1936
Illustrations: Plate 87 B; Text fig. 46, nos. 4-5 (p. 381).
Pileus 1-3.5 cm. broad, obtusely conic to campanulate when
young, frequently with a small, almost papillate umbo, becoming
broadly conic to plane with an obtuse umbo, the margin slightly incurved at first, splitting readily and in age frequently presenting a
ragged appearance, disc slightly rugose in large specimens, surface
striate, subvelvety, and dry but relatively transparent at maturity,
color "fuscous black" to "fuscous" on the umbo when young, fading
to "mummy brown" or "drab," margin paler and "avellaneous" to
"drab," not hygrophanous; flesh thickish on the disc and tapered
abruptly, whitish, rather fragile, odor and taste not distinctive;
lamellae adnate, becoming broadly uncinate to adnexed, close to
subdistant, 25-28 reach the stipe, two to four tiers of lamellulae,
broad and becoming ventricose (4-5 mm.), white, the edges dull
brown and denticulate; stipe 1-5 cm. long, 1-3 mm. thick, equal,
with a long (2-4 cm.), tapering pseudorhiza, stuffed but soon hollow,
tough and elastic, covered over all with a brown pruinose scurfiness,
somewhat glabrescent or with adhering patches of scurfiness in age,
pallid.
Spores bluntly ovate to broadly ellipsoid, 6-8 X 4-5 t, nonamyloid; basidia four-spored, 28-30 X 6-7 j; cheilocystidia subcylindric, clavate or somewhat fusoid, apices obtuse, 34-48 X 8-12 t,
filled with a brown substance; gill trama yellowish in iodine; pileus
almost lacking a pellicle, the hypoderm several cells deep, and its
cells with brown contents, subcylindric cystidium-like cells project
from this layer and cause the velvety appearance of the cap, tramal
body of narrower hyphae, all yellowish in iodine; caulocystidia abundant to scattered, with brown contents, 30-44 X 5-10,, variously
shaped; stipe tissue yellow in iodine.
Habit, habitat, and distribution.-Scattered to gregarious around
elm and ash stumps or on humus in elm and ash swamps, usually in
June; Michigan and Ontario. Not common.
Material studied.-Smith, 32-233, 32-540, 1316, 1348, 1408, 4694,
6292, 6381, 9524, 15103.
Observations.-The long pseudorhiza tapers to a thread and is
easily broken, which causes great difficulty in ascertaining its attachment. It probably arises from buried wood; at least I have never