Chapter II: ARCYRIA, Hill. Sporangia regular ovoid to cylindric, stipitate; the

wall a thin delicate membrane, circumscissile or torn away near the base, the upper portion evanescent, the lower part persistent, small and cup-shaped. Stipe more or less elongated, the interior containing roundish vesicles which become smaller upward, and gradually pass into the normal spores. Capillitium of slender tubules, issuing from the interior of the stipe, forming a complicated network, without any free extremities, the surface minutely warted or spinulose or with annular ridges. Spores globose, red, brown, yellow, cinereous.

§1. CLATHROIDES, Mich. Capillitium closely attached by a few threads which issue from the interior of the stipe, and are free from the calyculus (except in _A. punicea_), much elongated after dehiscence, weak and drooping or prostrate; the meshes open and irregular, not differing externally and internally, their threads similar throughout, the warts or ridges of the surface exhibiting a spiral arrangement.

1. ARCYRIA PUNICEA, Pers. Sporangium ovoid, more or less elongated; the calyculus small, plicate-sulcate. Stipe long, erect, brownish-red in color, expanded at the base into a small hypothallus. Capillitium firmly attached by numerous threads which are connate with the wall of the calyculus, much elongated after dehiscence, ovoid-oblong to cylindric, bright red in color, fading to red-brown or brownish-ochre; the threads uniform in thickness, about 3 mic., the surface with a series of prominent half-rings, which wind around the thread in a long spiral. Spores globose, even, 6-8 mic. in diameter.

Growing on old bark, wood, mosses, etc. The stipe 1-2 mm. in length, the capillitium elongated 2-4 mm. The commonest of the species, conspicuous by reason of its bright red color.

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.

6. ARCYRIA COOKEI, Mass. Sporangium ovoid-cylindric, the calyculus very small. Stipe long, erect, gray to mouse-color, darker below, arising from a thin hypothallus. Capillitium not much expanded after dehiscence, ovoid-cylindric, erect, gray to mouse-color; the superficial threads densely and uniformly covered with minute warts, 3-5 mic. in thickness; the threads of the interior thinner, about 2 mic. and smooth, or with very minute scattered warts. Spores globose, even, 6-8 mic. in diameter. See Plate I, Fig. 16.

Growing on old wood, mosses, etc. Capillitium 1-2 mm. long, the stipe about the same length. It seems as common as _Arcyria cinerea_, and has heretofore been included in it. See Massee's Monograph, p. 154.

7. ARCYRIA DIGITATA, Schw. Sporangium cylindric, the calyculus very small. Stipe long, ascending, brownish in color, usually several fasciculate or to some extent connate, the sporangia divergent at the apex. Capillitium not much expanded after dehiscence, cylindric, pale cinereous, or pale yellowish; the threads variable in thickness. 2-4 mic., those at the surface densely and minutely warted, those of the interior nearly smooth. Spores globose, even, 6-8 mic. in diameter.

Growing on old wood. Capillitium 2-4 mm. long, the stipe about the same length. _Arcyria bicolor_, B. & C.