Soluble empire-yellow pigment formed. Nitrites produced from nitrates. Aerobic. Optimum temperature, 25° C. Antagonistic properties: Some strains produce actinomycin. Source: Isolated from soil. Habitat: Soil. 16. Streptomyces parvus (Krainsky, 1914) Waksman and Henrici, 1948. (Actino- myces parvus Krainsky, Cent. f. Bakt., II Abt., 41, 1914, 622; Waksman and Henrici, in Manual, 6th ed., 1948, 939.) par'vus. L. adj. parvus small. Vegetative growth: Golden yellow to brick-red, depending on composition of medium. Aerial mycelium: Poorly developed, rose- white. Sporophores produce spirals. Spores spherical to ellipsoidal, 0.9 to 1.3 by 1.2 to 1.8 microns. Gelatin: Yellow colonies. Slow liquefac- tion. Ca-malate agar: Small, j'ellow colonies with light yellow aerial mycelium Starch agar: Same as on Ca-malate agar. Glucose agar: Same as on Ca-malate agar. Glucose broth: Hemispherical colonies in bottom of tube. Litmus milk : Rapidly coagulated and pep- tonized. Diastatic action good. Good growth on cellulose. Nitrites weakly produced from nitrates. Aerobic. Optimum temperature, 25° C. Antagonistic properties: Produces actino- mycin. Source: Isolated from garden soil. Habitat: Soil. with light brown reverse. Aerial mycelium powdery ash-gray to white. Yellow to yel- low-brown soluble pigment. Synthetic agar: Abundant, crumb-like, smooth, brownish growth. Aerial mycelium cottony white, later grayish or even reddish gray. Soluble light brown pigment, later yellow-brown. Glucose asparagine agar: Abundant, dif- fuse, colorless growth with light yellow reverse. Aerial mycelium powdery white. Soluble light yellow pigment. Ca-malate agar: Abundant, crumb-like growth with yellowish red reverse. Aerial mycelium velvety, white-gray or reddish gray. Soluble dark red-yellow pigment. Starch agar: Abundant, lichenoid growth. Aerial mycelium velvety, violet-gray. Solu- ble dark brown pigment. Glucose agar: Abundant, diffuse, color- less growth with light yellow reverse. Aerial mycelium abundant, powdery, seldom vel- vety, light brown. Soluble yellow pigment. Glucose broth: Very good, colorless sur- face growth, later producing heavy sedi- ment. Abundant flocculent particles. Aerial mycelium cottony, grayish white, tending later to disappear. Soluble light yellow pig- ment, becoming orange-yellow. Milk: Abundant, lichenoid growth. Aerial mycelium gray to violet. Soluble dark brown pigment. Actively peptonized. Potato: Abundant, lichenoid growth. Aerial mycelium powdery gray. No soluble pigment. Starch is rapidly hydrolyzed. No growth on cellulose. Antagonistic properties: Produces anti- biotics. Source: Isolated from soil. Habitat: Soil. 17. Streptomyces xanthophaeus Lin- denbein, 1952. (Arch. f. Mikrobiol., 17, 1952, 378.) xan.tho.phae'us. Gr. adj. xanthophaes golden, gleaming; M.L. adj. xanthophaeus shining like gold. Gelatin: Leathery, brown, abundant growth. Aerial mycelium velvety, ash-gray. Soluble yellow-brown pigment. Rapid liquefaction. Agar: Abundant, diffuse, smooth growth 18. Streptomyces cellulosae (Krainsky, 1914) Waksman and Henrici, 1948. (Actino- myces cellulosae Krainsky, Cent. f. Bakt., II Abt., 41, 1914, 662; Waksman and Hen- rici, in Manual, 6th ed., 1948, 938.) cel.lu.lo'sae. M.L. noun cellulosa cellu- lose; M.L. gen. noun cellulosae of cellulose. Vegetative growth: Yellow, producing soluble yellow pigment. No soluble brown pigment. Aerial mycelium: Well developed, gray to
