a. Elaters perfectly smooth.
5. Trichia varia, Pers. Sporangia globose, obovoid or somewhat irregular, gregarious and scattered or crowded, yellowish, ochraceous or olivaceous, sessile, or with a very short brown or blackish stipe. Mass of capillitium and spores yellow; elaters long, simple or sometimes branched a time or two, 4–5 mic. in thickness, ending in a smooth tapering point, 8–12 mic. long; spirals only two, smooth, very prominent in places, causing the elater to appear notched. Spores globose, oval or somewhat irregular, minutely warted, 10–14 mic. in diameter.
Growing in patches on old wood; a very common species. Sporangium .6-.8 mm. in diameter, or when irregular sometimes elongated to 1 mm. or more. Extremely variable as to the form of the sporangium, but readily recognized by its elaters.
6. Trichia Andersoni, Rex. Sporangia globose or obovoid, sessile, gregarious, closely crowded, or sometimes scattered, the wall thickened with minute scales, in color brownish-ochre or olivaceous. Mass of capillitium and spores yellow; elaters long, simple, 3–4 mic. in thickness, ending in a very long flexuous point, 14–18 mic. in length; spirals three or four, winding evenly and closely, perfectly smooth. Spores globose, minutely warted, 10–12 mic. in diameter.
Growing on the inside of bark of Acer. Sporangium .4-.5 mm. in diameter. The capillitium is deep orange and the spores olivaceous, but this difference in shade of color between spores and capillitium occurs in other species. Trichia advenula, Mass., is a closely related species, the swellings in the elaters having no specific value.
7. Trichia inconspicua, Rost. Sporangia very small, subglobose, sessile, collected together in clusters, or scattered, without any hypothallus; the wall brown, smooth and shining. Mass of capillitium and spores yellow; elaters long, simple, cylindric, 3–4 mic. in thickness, ending in smooth tapering points, 6–7 mic. in length; spirals three or four, close, not prominent, perfectly smooth. Spores globose, minutely warted, 10–12 mic. in diameter.
Growing on bark of Platanus, etc. New York, Peck; Iowa, McBride. The sporangia spherical or reniform and very small.
b. Elaters spinulose.
8. Trichia Iowensis, McBride. Sporangia subglobose, sessile, gregarious, scattered, or sometimes close and confluent; the wall thickened with minute scales, reddish-brown in color. Mass of capillitium and spores yellow; elaters quite variable, usually very long, but sometimes very short, simple, rarely branched, the thickness unequal, 3–4 mic. in the same elater, with occasional thicker swellings, bearing numerous scattered spines, usually about as long as the thickness of the elater, but sometimes much longer, those at the ends being similar; spirals three or four, fine and close, in places nearly obsolete. Spores globose, or more or less irregular, minutely warted, 9–11 mic. in diameter.
Growing on old bark of Populus; Iowa, McBride. Sporangia .4-.5 mm. in diameter. This is a very curious species of Trichia; it suggests Ophiotheca Wrightii, but the elaters are short and simple, and there is no question as to the spirals upon them. I could find no branched elaters in my specimen.