North American species of Mycena.

EUMYCENA: TYPICAE

305

nous), a well-differentiated hypoderm (the cells with brown contents), and the remainder filamentous, all parts except the pellicle
vinaceous brown in iodine.
Habit, habitat, and distribution.-Gregarious on humus in mixed
woods of fir and alder and scattered to subcespitose on decaying fir
logs during October and November; Michigan, Washington, and
California in the United States and Ontario and Manitoba in Canada.
Kauffman collected it in oak woods in Michigan. Apparently it is
quite rare in North America.
Material studied.-Smith, 2544, 9574, 3113, 8474, 14632, 1671%2
17495. Kauffman, three collections, Michigan.
Observations.-Mycena excisa is very similar to M. galericulata
in all its characters except the cystidia; in fact, Kauffman confused
the two, as is evidenced by his Michigan collections. M. excisa has
both the smooth and the roughened types of cheilocystidia, a feature
which Kauffman overlooked and which I did not fully appreciate in
my first study. The cystidia illustrated were all drawn from a single
section of one pileus and show the extreme variation. The colors
of the pileus and stipe are not distinctive, and the consistency is more
cartilaginous than that of either M. niveipes or M. algeriensis.
When revived in KOH, the pellicle gelatinizes very distinctly, so
that in a study of herbarium specimens one might be misled into
believing he has a different and distinctly viscid fungus. When
sections of fresh material are mounted in water, this character is not
evident. However, fruiting bodies which have been exposed to
continued wet weather often feel somewhat lubricous because of the
continued soaking, and in them the pellicle is usually slightly gelatinized. One must learn to make allowances for this condition.
149. Mycena tenuiceps, sp. nov.
Illustrations: Text fig. 36, nos. 5-7.
Pileus 1-3 cm. latus, obtusus demum planus vel subdepressus,
glaber, fuligineus, ad marginem pallidus, striatus; lamellae adnatae
vel subdecurrentes, angustae (3 mm. i), subdistantes, pruinosae,
pallide cinereae; stipes 1.5-3 cm. longus, 1.5-2.5 mm. crassus, aequalis,
fragilis, fistulosus, fuligineus, fibrillose punctatus, glabrescens; sporae
6-8 X 3.5-5,; pleurocystidia et cheilocystidia 50-95 X 10-16 t,
subventricosa. Specimen typicum in Herb. Univ. Mich. conserva