North American species of Mycena.

EUMYCENA: TYPICAE

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cle poorly defined, not separable, in other respects similar to the flesh.
Flesh very thin, blackish brown, fading to pallid grayish. Lamellae
not very close, unequal, three to five (seven) tiers of lamellulae,
simple, moderately broad, thickish, a bit ventricose, rounded, slightly
sinuate-adnate, white or grayish, especially toward the base. Edge
entire, somewhat obtuse, quite pale. Stipe moderately tenacious,
35-50 X 2-3 mm., equal, not bulbous, tubular or hollow, dark sordid
grayish brown, slightly furfuraceous-punctate, the particles rather
dark but stipe as a whole lighter than the pileus, dry. Practically no
odor or taste.
Basidia four-spored, 40-48 X 7.6-9 4; spores 7.5-9.4 X 5-5.5
(6) u, ellipsoid, amyloid; pleurocystidia and cheilocystidia similar,
numerous on the edge, scattered on the faces, large, 60-90 X 9-15 g,
irregularly cylindric or cylindric-fusoid, obtuse at the apex, hyaline;
gill trama with a broad filamentous central strand; covering of the
pileus distinctive. On the well-developed cellular hypoderm are
decumbent epicuticular, separate, very loose filaments which do not
mask the hypoderm. These hyphae have differentiated clavate extremities which at times are almost decumbent, subdecumbent, or
almost upright and then simulate a hymeniform layer, the cells of
which are free from each other. These hairs are 25-60 (120) X
6-18 L. They are packed with a dark-brownish pigment located in
the vacuoles; the epicuticular hyphae from which these arise are furnished with a second pigment located in peripheral incrusting plates.
The hairs on the stipe are numerous, are more or less grouped in
tufts, and resemble the pilocystidia except that they are more irregular. They measure 35-80 X 6-10 g and have the pigment in
the vacuoles. The hyphae of the pileus lamellae and stipe are not
amyloid.
I did not note the pigments in the pilocystidia and caulocystidia
of the Michigan collection. On revived material of the stipe the
contents of the apical cells still appeared sordid brownish, indicating
that a dark pigment was present in the fresh condition. In my specimens the caulocystidia were of two types; toward the apex they were
like those on the gills, but over the remainder they resembled those
on the pileus There is a discrepancy in spore shape between Josserand's material and mine, but, considering the variable number of
sterigmata produced on basidia in the Michigan collection, the discrepancy is best disregarded. Singer (1942) places this species in
Hydropus.