Sporangia gregarious or crowded, small, spherical, ellipsoidal or arcuate, brown or reddish brown, sessile; hypothallus none; capillitium dull, dark, ochraceous, the elaters long, slender, even, about 3 µ wide, the spirals three or four rather closely wound, the apices attenuate, acute, sometimes turned to one side; spore-mass concolorous, spores pale ochraceous, minutely but distinctly warted, 10–12 µ.

One of the smallest of the Trichiae, not uncommon in the Mississippi valley on decaying fallen stems of Populus—sp. Distinguished at sight from all except No. 3 following, by its small size and brown color. Under the lens the long, delicate, finely sculptured capillitial threads, with fine tapering threads are distinctive.

New England, New York, Pennsylvania, Illinois, Iowa, Missouri, Nebraska; Black Hills, South Dakota; Toronto.

2. Trichia contorta (Ditmar) Rost.

[Plate XIII]., Figs. 7, 7 a.

Sporangia gregarious, or crowded, small, ellipsoid or reniform, arcuate, dark red brown, sessile; hypothallus none; capillitial mass ochraceous or dull yellow, the elaters few, irregular, the spirals uneven, irregular, often projecting and thin, though generally flat or obscure, the apices more or less swollen, ending in a curved tip; spore-mass concolorous, spores beneath the lens bright yellow, papillose, 10–12 µ.

This species resembles the preceding in color, but is of less aggregate habit, and the sporangia are more plasmodiocarpous, reniform, arcuate, etc. The capillitium is also distinctive, the sculpture irregular, uneven with general lack of symmetry. Our description is made up from specimens of T. reniformis Peck, which appears to be the American form of Rostafinski's species.

Rare. New York, Montana?