wall
thin, smooth and shining; hypothallus none. Capillitium scanty, composed
of elaters habitually irregular and abnormal, intermingled with the
spores; elaters simple or sometimes branched, commonly very short, but
varying greatly in length, even in the same sporangium; the surface
marked with faint spirals, with a few annular ridges, minutely
punctulate or altogether smooth. Spores globose, yellow.

The species of this genus are to be regarded as degenerate Trichias. Of
course, the abnormality is exhibited most markedly by the elaters;
nevertheless, the sporangia of some of the species have a peculiar habit
of heaping themselves upon each other.

_A. Surface of the spores reticulate._

_a. Elaters with projecting rings._

1. OLIGONEMA NITENS, Lib. Sporangia subglobose, irregular, sessile,
closely crowded and heaped upon each other, the wall thin, yellow,
smooth and shining. Mass of capillitium and spores yellow; elaters
simple or sometimes branched, 3-4 mic. in thickness, with a few distant
projecting rings, the surface smooth between, or with very faint
spirals, the extremities obtuse, or sometimes with a minute apiculus.
Spores angularly or irregularly globose, the surface reticulate, 11-14
mic. in diameter.

Growing in small patches on and within rotten wood. Sporangia .4-.5 mm.
in diameter; the elaters variable, some with as many as a dozen
projecting rings, some with but a few or nearly smooth. _Trichia
nitens_, Libert.

2. OLIGONEMA PUSILLA, Schr. Sporangia subglobose, irregular, sessile,
scattered or collected together in heaps; the wall thin, yellow, smooth
and shining. Mass of capillitium and spores yellow; elaters simple or
sometimes branched, 4 mic. in thickness, sometimes with thicker inflated
portions, the surface marked with low faint spirals or perfectly smooth;
the extremities rounded and usually terminating in a smooth point, 3-5
mic. in length--this point either curved, bent to one side or turned
back, and twisted around the extremity as a ring. Spores angularly or
irregularly globose, the surface reticulate, 11-14 mic. in diameter.

Growing in small clusters in rotten wood. Sporangia .3-.5 mm. in
diameter; the elaters variable in length, scarcely exceeding 100 mic.
and often much shorter. _Trichia pusilla_, Schroeter.

_b. Elaters with no projecting rings._

3. OLIGONEMA FLAVIDUM, Peck. Sporangia obovoid to oblong, sessile,
closely crowded and irregular from mutual pressure; the wall th