1801. _Lycogala conica_ Pers., _Syn. Fung._, p. 159. 1875. _Dermodium conicum_ (Pers.) Rost., _Mon._, p. 284. Aethalia scattered, sometimes two or three together, small 2-4 mm. high, conical, sessile, pallid, grayish brown, marked by obscure black reticulations, opening regularly at the somewhat acuminate tip; peridium thin in structure, as in _L. epidendrum_, but more delicate; capillitium made up of abundant, slender, uniform threads almost smooth, simple, the free ends obtuse, taking origin in the cortex much as in the preceding species; spores in mass ochraceous, by transmitted light colorless, minutely warted or faintly reticulate, about 5 mu. A very distinct and rare little species. Well described by Persoon, who also appears to have observed the plasmodium "_primo rubra_." The color of the mature form varies with age; at first somewhat purplish. Dr. Rex collected it in Pennsylvania; Mr. Morgan has it from Ohio; our specimens are from southeastern Missouri. ORDER V =TRICHIALES= Fructification sporangial, rarely plasmodiocarpous, the sporangia stalked or sessile, gregarious or closely crowded, limeless throughout; the capillitium of definite threads, free or attached to the sporangial wall, isolated or combined into a net; spores generally some shade of yellow, never purple or black. The distinguishing feature in this order is found in the peculiar sculpture of the capillitial threads. This is suggested by the tubules of _Lycogala_, though probably the resemblance is superficial only. The individual threads, as in _Trichia_, are called elaters, from their probable efficiency in spore-dispersal. As here limited, the order is coextensive with the _Calonemeae_ of Rostafinski, except that that includes in addition the genera _Prototrichia_ and _Dianema_. The course of differentiation may be assumed to start with _Dianema_, through the _Perichaenaceae_ to the _Arcyriaceae_ and again from the same starting-point through _Prototrichia_ to the _Trichiaceae_. =Key to the Families of the Trichiales= _A._ Capillitial threads transverse to the sporangial cavity, attached usually at each end, plain or only slightly roughened _Dianemaceae_ _B._ Capillitium plain, papillose, or spinulose, often scanty, not netted, the threads sometimes attached by one end to the sporangium wall _Perichaenaceae_ _C._ Capillitium a distinct net, usually attached below to the sporangial wall; sculpture various, not continuous spiral bands _Arcyriaceae_ _D._ Capillitial threads transverse, fascicled, attached at both ends, but sculptured by well defined spiral bands _Prototrichiaceae_ _E._ Capillitial threads typically free, sometimes more or less branched, forming a loose net attached below, characterized by definite spiral bands, or sometimes by scattered rings _Trichiaceae_