North American species of Mycena.

180 NORTH AMERICAN SPECIES OF MYCENA

beneath a thin pellicle, the cells of which are covered with short rodlike projections, yellowish in iodine.
Habit, habitat, and distribution.-Gregarious to subcespitose on
bark, debris, or fallen leaves of deciduous trees in September and
October; vicinity of Ann Arbor, Michigan.
Material studied.-Smith, 32-471, 32-483, 32-492, 32-517, 32-616,
33-1059, 978, 11077, 15195.
Observations.-During the season of 1940, which was a very unusual year for agarics in the vicinity of Ann Arbor, specimens of this
species were found growing over the bark of a hop-hornbeam tree in
much the same manner as M. corticola. Ordinarily, fruiting bodies
occur in groups of two to five on debris under the fallen leaves, or
among mosses in oak woods.
This material has now been tentatively placed in M. roseocandida,
but it may be just a local variation of M. amabilissima. From field
experience it appears to me that in various parts of North America
there are many variations of these pink to rosy-red Mycenae with
fusoid pleurocystidia and that they do not differ enough from one
another to be classed as species. I have adhered to the traditional
concepts of the various species, however, in order to keep the present
treatment as consistent as possible with the existing literature, and
to avoid the confusion in the use of names which would certainly
arise from wholesale rearrangements. No matter how one treats the
species of this group, the same difficulties are always encountered.
82. MYCENA AMABILISSIMA (Pk.) Saccardo
Syll. Fung., 9: 37. 1891
Agaricus (Mycena) amabillissimus Peck, Ann. Rep. New York State Mus.,
39. 1887.
Prunulus amabilissimus Murrill, North Am. Flora, 9: 324. 1916.
Illustrations:
Plate 21 A, B; Text fig. 18, nos. 3, 5 (p. 183).
Smith, Mycologia, 27: 594, figs. a, b.
Pileus 3-20 mm. broad, obtuse, or conic at first, becoming broadly
conic or campanulate, sometimes expanded-umbonate, margin appressed against the stipe at first and in age often flaring or recurved,
surface glabrous, polished, lubricous when moist, color "light coral
red" (brilliant pinkish red) when young, fading to white in age or the
disc pale creamy, opaque or distinctly translucent-striate; flesh thin,