Sporangia gregarious, scattered, cylindric, erect, sometimes arcuate, obtuse, 2-3 mm. high, at first silvery, then brown, as the peridium vanishes, stipitate; stipe black, about one-half the total height or less; hypothallus distinct, more or less continuous, reddish-brown; columella tapering upward, black, attaining more or less completely the apex of the sporangium; capillitium, arising as rather stout branches of the capillitium, soon taking the form of slender, flexuous, brownish threads, which by repeated anastomosing form at length a close network, almost as in _Stemonitis_, the free, ultimate branches very delicate and short; spore-mass dark brown; spores by transmitted light, pale, almost smooth, except for the presence of a few scattered but very prominent umbo-like warts, of which four or five may be seen at one time, 5-7.5 mu. This is our most common North American species. It occurs everywhere on decaying wood, sometimes in remarkable quantity, thousands of sporangia at a time. The plasmodium, watery white in color, infests preferably very rotten logs of _Quercus_, on which in June the sporangia rise as white or pallid columns. The peridium is exceedingly delicate, less seldom seen here than in some other species, but likely to be overlooked entirely. The spores when fresh have a distinct violet or bluish tinge; in old specimens they are almost colorless. In any case they are well marked by the large papillae already referred to. _C. typhina_, var. _heterospora_ Rex, differs from the type in several particulars: the sporangia manifest a closer habit; the capillitium is made up of more slender threads and forms a yet denser network; the spores between the large papillae are marked by a more or less perfectly formed reticulation.[37] As to nomenclature, this is our old friend _C. typhina_ (Pers.) Rost. It should be, more properly, called _C. typhina_ Rost., for it is not Persoon's species exactly. But Scopoli, _l. c._, by citing Hall, Gleditsch, and Micheli, so describes our form as to leave small doubt that he had before him our common species. Schaeffer's figures also come to the rescue, which, though by no means satisfactory, yet can probably refer to no other species. However, Bulliard gives the first good account and figure, and in concord with the decision of our English colleagues, the name afforded by the famous _Champignons_ is here adopted. Widely distributed. Maine to California, and from British America to Nicaragua. 11. COMATRICHA ELEGANS (_Racib._) _List._ PLATE XVI., Fig. 12. 1884. _Rostafinskia elegans_ Racib., _Rozpr. Akad. Krak._, XII., 77. 1888. _Raciborskia elegans_ Berl., _Sacc. Syl._, VII., p. 400. 1894. _Raciborskia elegans_ Berl., List., _Mycet._, p. 133. 1909. _Comatricha elegans_ List., _Br. Mus. Guide to Mycet._, p. 31.