gray growth, becoming brown with purplish tinge; center raised. Margin yellow. Starch agar: Small, dark brown colonies. Glucose agar: Abundant, restricted, gray growth, becoming brown to dark brown. Glucose broth: Slight, flaky sediment. Litmus milk: Dark brown ring; coagu- lated; slowly peptonized, with faintly alka- line reaction. Potato: Restricted, orange to orange- red growth. Starch shows slight hydrolysis. Soluble dark brown pigment formed. Nitrites not produced from nitrates. Aerobic. Optimum temperature, 25° C. Antagonistic properties: Active against various bacteria. Source: Isolated once from Californian adobe soil. Habitat: Soil. 55. Streptomyces phaeochromogenes (Conn, 1917) Waksman and Henrici, 1948. (Actinomyces pheochromogenus (sic) Conn, N. Y. State Agr. Exp. Sta. Tech. Bull. No. 60, 1917, 16; Streptomyces phaeochromogenus (sic) Waksman and Henrici, in Manual, 6th ed., 1948, 943.) phae.o.chro.mo'ge.nes. Gr. adj. phaeus brown; Gr. noun chroma color; Gr. v. suffix -genes producing; M.L. adj. phaeochromo- genes producing brown color. Aerial mycelium: Branching filaments and hyphae, spirals narrow, open, elon- gated, sinistrorse. Gelatin stab: Abundant, spreading, cream-colored surface growth, becoming brown. Slow liquefaction. Agar: Thin, cream-colored growth, be- coming gray. Synthetic agar: Colorless growth, be- coming brown to almost black. Aerial my- celium abundant, white with brownish shade. Starch agar: Spreading, brownish growth, becoming brown. Glucose agar: Restricted, much folded, brown growth. Glucose broth: Dense, wrinkled pellicle. Litmus milk: Dark, almost black ring; coagulated, with slow peptonization ; faintly alkaline reaction. Potato: Brown to almost black growth. Starch is hydrolyzed. Soluble brown pigment formed. Nitrites produced from nitrates. Aerobic. Optimum temperature, 25° C. Antagonistic properties: Strong. Comment: One strain produces an anti- biotic, moldin (Maeda, Okami, Taya and Umezawa, Jap. Jour. Med. Sci. and Biol., 6, 1952, 327). Source: Isolated from soil. Habitat: Soil. 56. Streptomyces aureus (Waksman and Curtis, 1916) Waksman and Henrici, 1948. {Actinomyces aureus Waksman and Curtis, Soil Sci., 1, 1916, 124; Waksman and Henrici, in Manual, 6th ed., 1948, 943.) au're.us. L. adj. aureus golden. Aerial mycelium: Shows numerous spirals. Conidia spherical to ellipsoidal, 0.6 to 1.0 by 0.8 to 1.4 microns. Gelatin stab : Fair, cream-colored sui-face growth, becoming brown, spreading. Lique- faction. Agar: Restricted, gray growth. Synthetic agar: Thin, spreading, color- less growth. Aerial mycelium thin, gray, powdery, becoming cinnamon-drab. Starch agar: Thin, transparent, spreading growth. Glucose agar: Spreading, light orange growth; raised center; hyaline margin. Glucose broth: Thin, brownish ring; flaky sediment. Litmus milk: Black ring. No coagulation. Peptonization doubtful. Potato: Abundant, wrinkled, brown growth, becoming black. Starch is hydrolyzed. Soluble brown pigment formed. Nitrites produced from nitrates. Aerobic. Optimum temperature, 25° C. Antagonistic properties: Produces fungi- cidin, a substance active against various fungi. Some strains produce luteomycin. Source: Isolated many times from a variety of soils. Habitat: Soil. 67. Streptomyces tanashiensis Hata et al., 1952. (Hata, Ohki and Higuchi,
