spores are formed in chains. Aerobic. Saprophytic soil forms, less commonly parasitic on plants or animals. This genus can be divided, on the basis of the structure of the sporulating hyphae, into five groups: Group 1. Straight, sporulating hyphae, monopodial branching, never producing regular spirals. Group 2. Spore-bearing hyphae arranged in clusters. Group 3. Spiral formation in aerial mycelium; long, open spirals. Group 4. Spiral formation in aerial mycelium; short, compact spirals. Group 5. Spore-bearing hyphae arranged on mycelium in whorls or tufts. The type species is Streptornyces albiis (Rossi-Doria emend. Krainsky) Waksman and Henrici. Key to the species of genus Streptornyces. I. Saprophytes; psychrophilic to mesophilic. A. Soluble pigment on organic media absent or faint brown, pink, purple, golden yel- low or blue. 1. Pigment absent, or only faint brown pigment produced in protein media. a'. Aerial mycelium abundant, white. b'. Spirals formed; spores spherical to ellipsoidal. 1. Streptornyces albus h^. Long, open spirals; spores cylindrical. 2. Streptornyces longisporus . b'. Straight sporophores, forming broom-shaped clusters; spores spherical to ellipsoidal. 3. Streptornyces glohisporus. a^. Aerial mycelium whitish to light graj', in concentric zones. 4. Streptornyces anulatus. a^ Aerial mycelium on synthetic sucrose agar sandy lavender of dark gray. 5. Streptornyces rochei. 2. Aerial mycelium gray to blue-gray; soluble pigment blue. a^ Strongly proteolytic, b^ Spirals formed. c'. Pigment at first red, changing to blue. 6. Streptornyces coelicolor. c^. Pigment at first yellow-red, changing to blue or bluish green. 7. Streptornyces pluricolor. c^ Pigment unchanged with acidity. 8. Streptornyces cyaneus. b^. No spirals formed. 9. Streptornyces vinaceus. a^. Weakly proteolytic; aerial mycelium poorly developed. 10. Streptornyces violaceus. 3. Pigment at first green, becoming brown. a^ Aerial mycelium usually absent. 11. Streptornyces verne. a^. Aerial mycelium dark gray, olive-colored or gray-green. 12. Streptornyces viridans. 4. Growth pink on sj-nthetic media, yellowish on organic media; no soluble pig- ment. 13. Streptornyces calijornicus .
