Plasmodiocarp repent, reticulate, forming anon lines, circles, dots, etc., venulose pale yellow, ochraceous, at length whitish, the peridium thin, membranaceous, simple, fragile, but withal persistent, below united with a hypothallus which is more or less widely produced; capillitium rather scant, but abundantly charged with polygonal nodules of lime, yellow; spore-mass black; the spores, by transmitted light, violaceous, warted, globose, 10-13 mu. Plasmodium, at maturity, greenish-yellow. A very distinct species not likely to be confused with anything else, although in description, so far as concerns external characters, suggesting _Cienkowskia reticulata_. The two forms are not at all alike when placed side by side. For details as to the difference, see the description of the species last mentioned. Apparently not rare in eastern United States, Pennsylvania, Virginia, Ohio, Iowa. In 1805, Albertini and Schweinitz, _Conspectus Fungorum_, p. 251, t. 7, Fig. 2, described as _Physarum reticulatum_, a European form which became the basis of Rostafinski's genus _Cienkowskia_; see under that genus. Later, 1829, Schweinitz discovered in America a physarum-looking specimen which he took to be the same thing, and accordingly placed in his herbarium under this name, and entered _N. A. F._ 2295. Rostafinski further renamed another Schweinitzian species _Fuligo muscorum_ calling it, _Mon._, p. 111, _Physarum gyrosum_. Wingate and Rex apply in Ellis, _N. A. F._, this latter name to No. 2295 of Schweinitz. Such a reference is a mistake, judging from Rostafinski's descriptions and from the description and figure of Albertini and Schweinitz (_Consp. Fung._, p. 86, t. 7, I), and by the testimony of Lister. For further concerning Rostafinski's species, see under _Physarum gyrosum_, p. 111, _Mon._ 2. PHYSARUM LATERITIUM (_Berk. & Rav._) Rost. 1873. _Didymium lateritium_ Berk. & Rav., _Grev._, II., p. 65. 1875. _Physarum ditmari lateritium_ Rost., _Mon._, _App._, p. 9. 1879. _Physarum inequale_ Peck, _Rep. N. Y. Mus._, XXXI., p. 40. 1892. _Physarum chrysotrichum_ Berk. & C., Massee, p. 300. 1894. _Physarum inequale_ Peck, Lister, _Mycetozoa_, p. 60. 1896. _Physarum lateritium_ (Berk. & Rav.) Morg., _Jour. Cin. Soc._, p. 95. 1899. _Physarum lateritium_ (Berk. & Rav.) Morg., Macbr., _N. A. S._, p. 33. 1911. _Physarum lateritium_ Morg., List., _Mycetozoa, 2nd ed._, p. 82. Plasmodium scarlet. Sporangia gregarious, sessile, globose or sub-globose, or sometimes plasmodiocarpous, yellowish or orange, everywhere, when fresh, spotted with minute scarlet granules; the peridium thin, more or less rugulose; columella none; capillitium delicate, generally yellow, with nodules conspicuous, yellow or reddish; spores violet-brown in mass, by transmitted light pale violet, minutely roughened, 7-9 mu.