Most of the earlier authors, including Haller, used the generic name _Trichia_ to cover a variety of forms. It is here used with the limits sketched by De Bary in 1859 and 1864 (_Die Myxomyceten_), and followed more exactly ten years later by his pupil, Rostafinski. =Key to the Species of Trichia= _A._ Sporangia, in typical cases at least, wholly sessile. _a._ Gregarious; hypothallus none. i. Peridium brown or reddish brown. O Elaters smooth. OO Spirals even, regular 1. _T. inconspicua_ + Spirals irregular 2. _T. contorta_ ++ Elaters rough, spinescent 3. _T. iowensis_ ii. Peridium olivaceous or yellow. O Elaters smooth 4. _T. varia_ _b._ Hypothallus distinct; sporangia crowded; spores reticulate, banded, or netted. i. Spore-bands pitted 6. _T. persimilis_ ii. Spore-bands, narrow, plain 7. _T. favoginea_ iii. Spores covered by a delicate net 5. _T. scabra_ _B._ Sporangia stipitate. _a._ Hypothallus distinct 8. _T. verrucosa_ _b._ Hypothallus none; peridium checkered with pale reticulations. i. Brownish red or black 10. _T. botrytis_ ii. Olivaceous. O Elaters smooth 11. _T. subfusca_ OO Elaters rough 12. _T. erecta_ _c._ Peridium plain, shining 13. _T. decipiens_ _d._ Peridium plain, dull black 14. _T. lateritia_ 1. TRICHIA INCONSPICUA _Rostafinski._ PLATE III., Figs. 5, 5 _a_, 5 _b_. 1875. _Trichia inconspicua_ Rost., _Mon._, p. 259. 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 mu 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 mu. 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_. 1811. _Lycogala contortum_ Ditmar, Sturm, _Deutsch. Fl._, III., Tab. 5. 1872. _Trichia reniformis_ Peck, _Rep. N. Y. Mus._, XXVI., p. 74. 1875. _Trichia contorta_ Rost., _Mon._, p. 259.