North American species of Mycena.

462 NORTH AMERICAN SPECIES OF MYCENA

ened walls. They are ventricose, with only an inconspicuous neck
and obtuse apex, or are nearly cylindric. The gill trama is gelatinous
and made up of very slender hyphae (4-5 t, thick). The pileus trama
is also gelatinous beneath a surface palisade of more or less uprightclavate to pear-shaped nongelatinous cells which have homogeneous
dark-brown contents. Numerous hyaline setae 100-250 X 9-18 u
arise from this layer, in addition to pilocystidia which resemble those
on the gills in size, shape, and markings, or are merely thin-walled.
The setae have thin or only slightly thickened walls. Most of them
collapse very readily and are difficult to revive. The tramae of the
pileus and gills are yellowish in iodine. The fruiting bodies revive
very well and are rather leathery in consistency. Numerous caulocystidia similar to the setae and pilocystidia are present over the
surface of the stipe. The tissue of the stipe is yellow in iodine.
The microscopic characters of this species are very distinctive and
indicate a relationship to Heliomyces. The gelatinous tramae of the
gills and pileus, of course, exclude it from Mycena. There seems to
me to be no point in transferring it to another genus until generic
concepts in tropical agarics have been clarified on the basis of extensive anatomical studies correlated with critical observations on
fresh material.
MYCENA SYRINGEA Murrill
Mycologia, 8: 221. 1916
Prunulus syringeus Murrill, North Am. Flora, 9: 341. 1916.
"Pileus minute, hemispheric, solitary, 5 mm. broad, 3 mm. high;
surface lilac-colored, fulvous on the disk, subgranulose in appearance, margin entire, concolorous: lamellae distant, inserted, rather
broad, adnate, violet-colored: spores globose or subglobose, smooth,
hyaline, about 4,u: stipe cylindric, equal, glabrous, melleous, lilaccolored at the apex, 2 cm. long, less than 1 mm. thick.
"Type collected in humus in woods in Troy and Tyre, Cockpit
Country, Jamaica, 600 m. elevation, January 12-14, 1909, W. A.
Murrill & W. Harris 1097 (herb. N. Y. Bot. Gard.).
"Distribution: Known only from the type locality."
The type has been examined and the spores have been found to be
globose, smooth, hyaline, 3-4,u, and nonamyloid. The basidia are
four-spored. No differentiated cystidia were seen on the sides or
edges of the gills. The gill trama is homogeneous and made up of