18 ACTINOMYCETES 



2. Surface growth heavy on glycerol synthetic solution with abun- 



dant aerial mycelium. 



a. Aerial mycelium on nutrient potato agar limited, pale gray. 



119. Streptomyces gracilis 



b. Aerial mycelium on nutrient potato agar abundant, white; 

 gelatin liquefaction stratiform; no soluble pigment. 



120. Streptomyces praecox 



c. Gelatin liquefaction stratiform; soluble pigment produced. 



121. Streptomyces setonii 



d. Abundant aerial mycelium on nearly all media; pigment on 

 calcium malate-glycerol agar carnelian red. 



122. Streptomyces praefecundus 



3. Surface growth fair on glycerol synthetic solution with some 

 aerial mycelium. 



a. Soluble pigment (often green) produced on all solid media. 



123. Streptomyces viridogenes 



b. Soluble pigment (yellow) produced on all synthetic media. 



124. Streptomyces loidensis 



c. Soluble pigment none or only poor; decided clot produced in 

 milk. 



125. Streptomyces wedmorensis 



4. Surface growth scant or none, but some bottom growth on 

 glycerol synthetic solution. 



a. Color changes produced in brom-cresol milk. 



a 1 . Tyrosinase positive; no aerial mycelium on nutrient po- 

 tato agar. 



126. Streptomyces scabies 



b 1 . Tyrosinase negative; aerial mycelium produced on all 

 solid media. 



a 2 . Aerial mycelium on synthetic sucrose agar abundant. 

 a 3 . Growth good on egg-albumen agar with abundant 

 aerial mycelium. 



127. Streptomyces tenuis 



b 3 . Growth poor on egg-albumen agar with scant 

 aerial mycelium. 



128. Streptomyces marginatus 



b 2 . Aerial mycelium on synthetic sucrose agar scant; no 

 true aerial mycelium produced on any media; colonies 

 often show dark centers. 



129. Streptomyces salmonicolor 



b. No color changes produced in brom-cresol milk. 



a 1 . Facultative anaerobe; no true aerial mycelium, or only 



