Sporangia minute, either closely combined and superimposed, so as to form a pulvinate aethalium, or crowded together in a single layer, sessile, or short-stipitate; the peridia thin, membranous, marked by scattered plasmodic granules, often lustrous, sometimes dull lead-colored or blackish, especially above; stipe, when present, very short but distinct, brown, rugulose; hypothallus well developed, membranous, or more or less spongiose in structure; spore-mass ochraceous, under the lens, nearly smooth, almost colorless, 6-7.5 mu. This very variable species has been well studied by Dr. Rex. See _Bot. Gaz._, XVII., p. 201. In its simpler phases it presents but a single layer of sporangia generally closely crowded together, sometimes free and even short stipitate! In the more complex phase the sporangia are heaped together in a pulvinate mass in which the peridia appear as boundaries of minute cells. In this case the outermost sporangia are often consolidated to form a cortex more or less dense and shining. In any case the hypothallus is a prominent feature; generally laminated and of two or three layers, it is in the more hemispheric aethalia very much more complex, sponge-like. When thin this structure is remarkable for its wide extent, 40-50 cm.! The simpler forms approach very near to _Cribraria_ through _C. argillacea_. The most complex remind us of _Enteridium_. This is _Perichaena caespitosa_ Peck. In this country it has, however, been generally distributed as _L. effusa_ Ehr. This author throws some doubt on the species he describes by suggesting that the plasmodium may be _red_. The description, however, and figures are otherwise good and are established by the usage of Rostafinski. The plasmodium has much the same color as the mature fruit. Widely distributed. New England to the Black Hills and Colorado, south to Arkansas. California, about Monterey. =2. Tubifera= _Gmelin_ 1791. _Tubifera_ Gmelin, _Syst. Nat._, II., p. 1472. Sporangia tubular, by mutual pressure more or less prismatic, connate, pale ferruginous-brown, iridescent, the walls thin, slightly granular, long-persistent; dehiscence apical; hypothallus thick, spongiose, white or whitish; spore-mass ferruginous. This genus is easily recognized by the tubular sporangia, destitute of capillitial threads, seated upon a strongly developed hypothallus. The synonymy of the case is somewhat difficult. It is possible that Mueller's _Tubulifera ceratum, Fl. Dan._, Ellevte Haefte, 1775, p. 8, may belong here, but neither the text nor the figures make it certain. Neither he nor OEder, who gives us _T. cremor_ in the same work, had any accurate idea of the objects described. Gmelin's description of _Tubifera_, II., 2, 1472, is, however, ample, and his citations of Bulliard's plates leave no doubt as to the forms he included. Gmelin writes: "Thecae (membranae expansae superimpositae) inter se connatae seminibus nudiusculis repletae."