North American species of Mycena.

EUMYCENA: DEMINUTIVAE

83

Spores 7-9 (11.5) X 2.5-3 g, subcylindric, smooth, nonamyloid;
basidia four-spored (and two-spored?); no pleurocystidia seen;
cheilocystidia abundant, 26-38 X 5-9,, usually subfiliform and with
irregular outlines, the base usually slightly enlarged; gill trama homogeneous, yellowish in iodine; pileus trama with a thin adnate pellicle
made up of narrow (3-5, thick) hyphae the walls of which are
covered with numerous short projections, from this layer arise numerous pilocystidia similar in size and shape to the cheilocystidia,
homogeneous beneath the pellicle; caulocystidia abundant, similar to
the cheilocystidia or longer (up to 50,).
Habit, habitat, and distribution.-Gregarious on cedar twigs (Thuja
plicata); Blue River, Oregon. Known only from the type locality.
Material studied.-Smith, 7810.
Observations.-The spore size is apparently based on a mixture
of two ranges, one very likely from four-spored basidia and the other
from two-spored individuals. I was not able, however, to demonstrate conclusively the presence of the latter. Although the pileus
was not papillate, the presence or the lack of a papilla is not of great
significance in such small fungi as this and should not be emphasized.
The important diagnostic character which separates M. albicolor from
M. gracilis is the presence of numerous cystidia over the pileus and
stipe and along the edges of the lamellae. The arcuate gills furnish
an additional character to distinguish the two. M. albicolor was
referred at first to M. angustispora (Joss.) Ktihner. The latter, however, is reported as not having cheilocystidia and as having the base
of the stipe somewhat fuscescent. In view of the fact that Josserand
made an exhaustive anatomical study of his fungus, the difference
noted in the cheilocystidia is important. The abundant cheilocystidia
also distinguish M. albicolor from M. pseudocrispula.
18. Mycena filiformis, sp. nov.
Illustrations: Text fig. 6, nos. 5-6 (p. 85).
Pileus 1-5 mm. latus, convexus, membranaceus, candidus, glaber
vel pruinosus; lamellae distantes, angustae, late adnatae vel subdecurrentes, candidae; stipes 10-15 mm. longus, filiformis, albidus,
pruinosus; sporae 9-12 X 2.5-3,; basidia tetraspora; pleurocystidia
et cheilocystidia 26-32 X 5-8 i, levia. Specimen typicum in Herb.
Univ. Mich. conservatum. Legit A. H. Smith, n. 15531, prope Milford, Mich., Nov. 5, 1940.
Pileus 1-5 mm. broad, convex with an inrolled margin, mem