Polyangiden. Geb. Borntraeger, Leipzig, 1924, 73.) so.re.di.a'tum. Gr. noun sorus a heap; M.L. dim. noun soredium a little heap, a soredium; M.L. adj. sorediatus having little heaps. Vegetative cells: Rods 0.8 by 3 to 5 mi- crons. Attempts to cultivate have failed. Fruiting body: Orange-red, irregularly lobed, consisting of a compact mass of small angular cysts. Average size of cysts, 6 to 7 microns; smallest, 3 microns, with thick and sharply defined edges. Rods 0.8 by 3 to 5 microns. The Krzemieniewskis (Acta Soc. Bot. Poloniae, 1927, 96) have described a variety, Sorangium sorediatum var. macro- cystum, consisting of cysts 6 to 14 by 7 to 16 microns, about twice as large as those in the type species. Source: Reported by Thaxter (op. cit., 1904, 414) on rabbit dung from South Caro- lina. Habitat : Found on decaying organic mat- ter in soil and in the dung of various ani- mals. Common in Polish soils (Krzemieniew- ski, o-p. cit., 1927, 96). Illustrations: Thaxter {op. cit., 1904, PI. 27, Figs. 22-24), Quehl (Cent. f. Bakt., II Abt., 16, 1906, 9, PI. 1, Fig. 2), Jahn (Kryp- togamen-fiora d. Mark Brandenburg, V, Pilze I, Lief 2, 1911, 202, Fig. 1) and Krze- mieniewski (Acta Soc. Bot. Pol., 4, 1926, PI. IV, Figs. 39-41; also see ibid., 1927, PI. V, Fig. 17, var. macrocystum, Fig. 18). 3. Sorangium cellulosum Imsenecki and Solntzeva, 1937. (Microbiologia, 6, 1937, 7.) cel.lu.lo'sum. M.L. noun cellulosum cel- lulose. Vegetative cells: Flexible and rod-shaped with rounded ends, 0.4 to 0.6 by 2.2 to 4.5 microns, occurring singly. Fruiting body: Mature fruiting body rusty brown, 400 to 500 microns in diameter, sessile on layer of partially dried slime. No outer wall or limiting membrane. Composed of numerous cysts, irregular in shape, 1.6 to 3.2 microns in diameter, each containing less than ten shortened rods. No discernible cyst wall or membrane. Resting cells: 0.3 by 1.5 to 2.0 microns (no other data). Vegetative colony: No data. Physiology: Good growth on starch and cellulose. Decomposes up to 24 per cent cellulose in ten days but does not form fruiting bodies. Very poor growth on arabi- nose with the formation of many involution forms including very much elongated cells. Fails to grow on nutrient agar, washed agar, potato, carrot or milk. Source: Isolated from soil. Habitat: Soil. Decomposes organic matter. 4. Sorangium spumosum Krzemien- iewski and Krzemieniewska, 1927. (Acta Soc. Bot. Poloniae, 5, 1927, 97.) spu.mo'sum. L. adj. spumosus foamy or frothy. Vegetative cells: Rods 0.7 to 0.9 by 2.6 to 5.2 microns. Fruiting bodies: Consist of numerous cj'sts, spherical or ellipsoidal, not sur- rounded b}^ a common membrane but united into bodies embedded in slime. Often in double or single rows. Cyst walls colorless, or slightly brownish, transparent, so that the characteristic arrangement of the rods may be seen within. Cysts 8 to 26 by 7 to 20 microns. Source: From Polish soil; also isolated from rabbit dung. Habitat : Found on decaying organic mat- ter in soil and in the dung of various ani- mals. Illustrations: Krzemieniewski (ibid., PI. V, Fig. 19). 5. Sorangium septatum (Thaxter, 1904) Jahn, 1924. (Polyangium septatum Thaxter, Bot. Gaz., 37, 1904, 412; Jahn, Beitrage zur bot. Protistologie. I, Die Polyangiden, Geb. Borntraeger, Leipzig, 1924, 75.) sep.ta'tum. L. adj. septatus fenced, i.e., divided by walls. Vegetative cells: Rods 0.8 to 1.0 by 3.0 to 5.0 microns. limiting bodies: Yellowish orange. When dried, dark orange-red, 50 microns to more than 100 microns in diameter, cysts rounded or ellipsoidal, angular or cylindrical, inner portion of the envelope divided into a var- iable number of secondary cysts. Cysts 18 to 22 by 12 to 22 microns in diameter. Sec-
