5 turns. Spores spherical to ellipsoidal, 0.6 to 0.8 by 0.7 to 0.9 micron. Gelatin: Slow liquefaction after 20 to 30 days' incubation. Milk: Weakly peptonized, usually with- out previous coagulation. Potato: Soluble brown pigment. Sucrose not inverted. Starch is slowly hydrolyzed. No growth on cellulose. Fats rapidly hydrolyzed and utilized. Paraffin: Good growth with spiral-form- ing sporophores and spherical spores. Nitrites not produced from nitrates. Antagonistic properties: Strongly an- tagonistic. Comment: This species represents a widely distributed group of organisms in- cluding such forms as Actinomyces parvus of Krainsky and others. Source: Isolated from soil. Habitat: Soil. 30. Streptomyces griseolus (Waksman, 1923) Waksman and Henrici, 1948. (Actino- myces 96, Waksman, Soil Sci., 8, 1919, 121; Actinomyces griseolus Waksman, in Manual, 1st ed., 1923, 369; Waksman and Henrici, in Manual, 6th ed., 1948, 938.) gri.se 'o.lus. Old French adj. gris gray; Med.L. adj. griseus gray; M.L. dim. adj. griseolus somewhat gray. Aerial mycelium: No spirals observed. Conidia spherical or ellipsoidal. Gelatin stab: Liquefied with yellowish, flaky pellicle and sediment. Agar: Brownish growth with smooth sur- face. Synthetic agar: Colorless, thin, spreading growth, chiefly in the medium; surface growth limited almost entirely to the aerial mycelium. Aerial mycelium at first gray, later becoming pallid, neutral gray. Starch agar: Grayish brown growth with dark ring. Glucose agar: Spreading growth, both on the surface and into the medium; center raised, cream-colored, turning dark. Glucose broth: Thick, brown ring. Litmus milk: Abundant growth, pink pellicle; coagulated; peptonized, becoming alkaline. Potato: Cream-colored growth, becoming black, spreading. Starch is hydrolj^zed. Faint brownish soluble pigment formed. Nitrites produced from nitrates. Aerobic. Optimum temperature, 25° C. Antagonistic properties: Considerable ac- tivity against various bacteria; some of the strains show negative activity. Source: Isolated from soil. Habitat: Soil. 31. Streptomyces fasciculus (Krassil- nikov, 1941) Waksman, 1953. (Actinomyces fasciculus Krassilnikov, Guide to the Ac- tinomycetes, Izd. Akad. Nauk, U.S.S.R., Moskau, 1941, 51; Waksman, in Waksman and Lechevalier, Actinomj^cetes and Their Antibiotics, Baltimore, 1953, 54.) fas.ci'cu.lus. L. mas. dim. n. fasciculus a small bundle. Vegetative growth: Good growth, lich- enoid, colorless, covered with dark gray, powdery or velvety aerial mycelium. Aerial mycelium: Sporophores straight, short, arranged in broom-shaped bodies or fascicles. Spores oblong, 0.7 by 1.0 to 1.5 microns. Gelatin: Liquefaction. Agar: Aerial mycelium poorly developed, gray. Synthetic agar: Typical vegetative growth. Milk: Readily coagulated and peptonized. Potato: Heavy, folded growth with well developed, dark gray aerial mycelium. Soluble brown pigment. Sporophores and spores same as on synthetic agar. Sucrose is readily inverted. Starch is rapidly hydrolyzed. Good growth on cellulose. Nitrites weakly produced from nitrates. Antagonistic properties : Strongly antago- nistic. Relationship to other species : Related to Streptomyces candidus. Source: Isolated from soil. Habitat: Soil. 32. Streptomyces erythraeus (Waksman, 1923) Waksman and Henrici, 1948. (Actino-
