IV. STEMONITIS, Gled. Sporangia subcylindric, elongated, stipitate, standing close together on a well-developed common hypothallus, the wall very thin and evanescent. Stipe brown or black, smooth and shining, tapering upward, entering the sporangium and prolonged nearly to the apex as a slender columella, the stipe shorter than the columella. Capillitium arising from numerous points of the columella throughout its entire length; the threads immediately branch and anastomose to form an interior network of large meshes, they then spread out next the wall of the sporangium into a superficial network of smaller meshes. Spores globose, brown or violaceous. In this genus there are two distinctly differentiated series in the capillitium, the one an interior supporting network of large meshes, the other a superficial network of smaller meshes; sometimes the superficial network disappears or is wanting toward the upper part of the capillitium, there is then an approach to Comatricha. Very minute scattered branchlets usually connect the superficial network with the wall of the sporangium. §1. DICTYNNA. Threads of the capillitium arising from numerous points of the columella, immediately branching several times and anastomosing to form the interior network of large meshes; the superficial network consisting of small irregular and unequal meshes, varying from smaller than the spores to two or three times their diameter. 1. STEMONITIS FUSCA, Roth. Sporangia elongated, subcylindric, tapering and obtuse at the apex, tapering gradually downward, growing closely crowded together on a strongly-developed brown hypothallus. Stipe and columella smooth and black, tapering gradually upward and disappearing near the apex of the sporangium, the stipe shorter than the columella. Capillitium of slender brown or blackish threads, which immediately branch and anastomose, forming a dense interior network of large irregular meshes, the ultimate branchlets of which support a superficial network of small polygonal meshes. Spores globose, dark violaceous, the surface minutely warted, the warts with a reticulate arrangement, 7-9 mic. in diameter. Growing on old wood, bark, leaves, etc.; common everywhere. Sporangium with the stipe 6-15 mm. in height, the sporangium .3-.4 mm. in thickness, the stipe variable in length, but always shorter than the sporangium. The meshes of the superficial net vary in size in the same sporangium, being usually 5-25 mic. in width, but sometimes they are larger, ranging from 10-40 mic. in extent. The name _Stemonitis maxima_ was given by Schweinitz to some unusually large specimens which grew on a Polyporus. _Stemonitis dictyospora_ of Rostafinski's monograph, with spores 12 mic. in diameter, is said to occur in South Carolina; I have seen no specimens.