Key to the species of genus Podangium. I. Stalk scarcely definite, cysts short, appressed, if elongate then passing over from the white stem into the club-shaped cyst. Ripe cysts chestnut -brown. 1. Podangium erectum. II. Stalk well differentiated. A. Cysts spherical, often irregular, confluent. 2. Podangium lichenicolum . B. Cysts not spherical, regular in shape, distinct. 1. Cysts lengthened, ellipsoidal. 3. Podangium gracilipes. 2. Cysts flattened, like cap of Boletus. 4. Podangium boletus. 1. Podangium erectum (Schroeter, 1886) Jahn, 1924. (Cystobacter erectus Schroe- ter, in Cohn, Kryptogamenflora v. Schle- sien, 3, 1, 1886, 170; Chondromyces erectus Thaxter, Bot. Gaz., 23, 1897, 407; Jahn, Beitrage zur bot. Protistologie. I, Die Poly- angiden. Geb. Borntraeger, Leipzig, 1924, 80.) e.rec'tum. L. adj. erectus erect. Swarm stage (pseudoplasmodium) : Kofler states rods are 2 to 5 microns in length. Fruiting bodies: Cysts usually short, almost spherical, compact, rounded above, orange-red changing to chestnut-brown, single on a white to yellow hypothallus con- stituted from the .slime remaining behind. A definite "foot" of whitish slime is seldom observed. Fifty to hundreds together. Usu- ally about 80 microns high and 40 to 50 mi- crons broad above, smaller below, often spherical cysts 60 microns in diameter. Rods in cysts 0.6 by 4 microns. Jahn believes the European form to be distinct from that described by Thaxter. Thaxter's form produces cystophores 60 to 300 microns long which wither at maturity so that cysts appear sessile. Source: Isolated by Thaxter (op. cit., 1897, 407) from horse dung in laboratory cultures, Massachusetts; also found on bark covered with lichens (Jahn, op. cit., 1924, 80). Habitat: Found on decaying organic mat- ter in soil and in the dung of various ani- mals. Illustrations: Thaxter {op. cit., PI. 31, Figs. 16-19), Quehl (Cent. f. Bakt., II Abt., 16, 1906, PI. 1, Fig. 4), Jahn {op. cit., 1924, PI. 1, Figs. 7-9) and Krzemieniewski (Acta Soc. Bot. Poloniae, 4, 1926, 1, PI. V, Figs. 52-53). 2. Podangium lichenicolum (Thaxter, 1892) Jahn, 1924. {Chondromyces lichenicolus Thaxter, Bot. Gaz., 17, 1892, 402; Jahn, Beitrage zur bot. Protistologie. I, Die Poly- angiden. Geb. Borntraeger, Leipzig, 1924, 81.) li.che.ni'co.lum. Gr. noun lichen a tree moss, lichen; L. v. colo to dwell; M.L. adj. lichenicolus lichen-dwelling. Swarm stage: Reddish, rods cjdindrical, tapering slightly, 0.6 by 5.0 to 7.0 microns. Germinate readily after drying for 18 months when sown on moist lichens. Fruiting bodies: Cysts single, rounded or irregularly lobed, often confluent. Cysto- phore short, squarish, often lacking or mis- shapen. Cysts 28 to 35 microns, stem 7 to 8 by 10 microns. Source: Isolated from lichens from New Haven, Conn. Habitat: Found on lichens and algae as well as on wet boards. Illustrations: Thaxter {op. cit., 1892, PL 23, Figs. 20-23) and Quehl (Cent. f. Bakt., II Abt., 16, 1906, 9, PL 1, Fig. 6). 3. Podangium gracilipes (Thaxter, 1897) Jahn, 1924. {Chondromyces gracilipes Thaxter, Bot. Gaz., 23, 1897, 406; Jahn, Beitrage zur bot. Protistologie. I, Die Poly- angiden. Geb. Borntraeger, Leipzig, 1924, 82; Chondromyces minor Krzemieniewski, Acta Soc. Bot. Poloniae, 7, 1930, 265.) gra.ci'li.pes. L. adj. gracilipes slender - footed. Swarm stage: Rods 5 to 7 microns.
