2. ARCYRIA MINOR, Schw. Sporangium ovoid-oblong; the calyculus small, sulcate and ribbed, granulose. Stipe short, erect, brownish-red in color, standing on a thin hypothallus. Capillitium much elongated after dehiscence, oblong to cylindric, lax and prostrate, bright red to brownish in color; the threads uniform in thickness, 2.5-3 mic., the surface with a series of prominent half-rings, which wind around the thread in a long spiral. Spores globose, even, 7-9 mic. in diameter. See Plate I, Fig. 17. Growing on old wood, bark, Polyporus, etc. The stipe .4-.7 mm. in length, the capillitium elongated 1.5-3 mm. Not uncommon, but it is usually referred to _A. adnata_. 3. ARCYRIA ADNATA, Batsch. Sporangium ovoid; the calyculus very small, finely ribbed and granulose. Stipe very short or entirely wanting. Capillitium much expanded after dehiscence, globose or obovoid, pale red to brownish in color; the threads uniform in thickness, about 4 mic., the surface with a series of prominent half-rings with mingled warts and spines, which wind around the thread in a long spiral. Spores globose, even, 6-8 mic. in diameter. Growing in small clusters on old wood. A small species, the capillitium expanded 1-2 mm., the stipe extremely short, or altogether absent. 4. ARCYRIA NUTANS, Bull. Sporangium cylindric; the calyculus small, granulose, ribbed and sulcate. Stipe very short, arising from a common hypothallus. Capillitium greatly elongated after dehiscence, cylindric, drooping and pendulous, pale yellow or pale ochraceous; the threads 3-4 mic. in thickness, the surface covered with spinules, among which are rings and half-rings, with an indistinct spiral arrangement. Spores globose, even, 7-9 mic. in diameter. Growing on old wood. The capillitium elongated 4-8 mm., the stipe very short. A very conspicuous species by reason of its long pale yellow capillitium. §2. PLECTANELLA. Capillitium erect, firmly attached by numerous threads, which issue from the interior of the stipe, but are connate with the wall of the calyculus, after dehiscence not much expanded: the meshes at the surface of the network much smaller than those within, folded back and forth, narrow and irregular, their threads densely warted or spinulose; the meshes of the interior much larger, open and expanded, their threads with minute scattered warts or perfectly smooth. 5. ARCYRIA CINEREA, Bull. Sporangium ovoid or oblong-ovoid; the calyculus very small. Stipe long, erect, cinereous, becoming blackish, standing on a thin hypothallus. Capillitium not much expanded after dehiscence, ovoid-oblong, erect, pale cinereous, sometimes pale yellowish; the external threads densely spinulose, 2-3 mic. in thickness; the threads of the interior thicker, 3-5 mic., and very minutely warted or quite smooth. Spores globose, even, 6-8 mic. in diameter. Growing on old wood. Capillitium 1-2 mm. long, the stipe about the same length.