5. Under high magnifying power, fine ridges are sometimes seen running lengthwise of the elaters, bridging the intervals between the spirals. These were first observed by DeBary, in _Trichia chrysosperma_, but they have since been seen in the elaters of nearly every other species of Trichia, and also in species of Hemiarcyria. The few species with elaters, so far as yet known, habitually irregular, defective and abnormal, are referred to the genus Oligonema. The normal species of Trichia arrange themselves quite naturally into three sections. §1. A NACTIUM. Sporangia varying from globose to pyriform or turbinate, supported on a more or less elongated stipe. Spores globose, the surface minutely warted. _a. Elaters with very long tapering extremities._ 1. TRICHIA FRAGILIS, Sow. Sporangia obovoid to pyriform or clavate, often fasciculate, stipitate; the wall a thin membrane, with a thick dense outer layer of brown-red granules. Stipes long, erect or curved, simple or usually fasciculate and often connate, arising from a thin hypothallus. Mass of spores and capillitium from reddish-brown to yellow and ochraceous; elaters simple, rarely branched, 4-5 mic. thick, with very long tapering extremities, ending in smooth points 8-12 mic. long; spirals, three or four, perfectly smooth. Spores globose, minutely warted, 10-12 mic. in diameter. Growing on old wood. Sporangia with the stipe 2-4 mm. in height, the sporangium .6-.8 mm. in diameter, the stipe usually longer than the sporangium. The color quite variable, mostly dull red-brown or blackish-brown, more rarely yellow or coffee-brown, usually opaque, rarely shining. 2. TRICHIA FALLAX, Pers. Sporangium obovoid to pyriform or turbinate, rarely clavate, stipitate; the wall thin, smooth and shining, colored as the spores and capillitium. Stipe more or less elongated, simple, erect, brownish below, filled with roundish vesicles. Mass of capillitium and spores yellowish, ochraceous or olivaceous; elaters simple or sometimes with several branches, 4-6 mic. thick in the middle, tapering gradually to each extremity, ending in smooth tapering points, 20-40 mic. in length; spirals, three, perfectly smooth. Spores globose, minutely warted, 10-12 mic. in diameter. See Plate I, Fig. 22. Growing on old wood. Sporangium with the stipe 2-4 mm. in height, sporangium .6-.8 mm. in diameter, the stipe usually longer than the sporangium. Under high magnifying power the spores are seen to be minutely reticulated. _b. Elaters cylindric, ending in a smooth tapering point._