112 



THE ACTINOMYCETES, Vol. II 



Sucrose nitrate agar: Growth at room 

 temperature poor to fair, flat or slightly 

 elevated. Margin smooth or scalloped, sec- 

 toring frequent. Color pale buff to tawny, 

 changing in some old cultures to brown with 

 a lighter margin. Forms a compact surface 

 layer, made up mostly of distinct palisades, 

 and a submerged region of loosely arranged 

 hyphae. Surface region frequently stratose in 

 old cultures, with narrow, orange-colored 

 layers. Sporangia fairly abundant in some 

 cultures, not formed in others; spherical to 

 irregular; frequently beneath the surface in 



old cultures, owing to overgrowth by pali- 

 sade hyphae. Sometimes a new layer of 

 sporangia forms over the first layer. Odor 

 slightly fragrant. Usually colors the agar 

 pale yellow. 



Glucose-asparagine agar: Growth good to 

 very good, consisting of a central area of 

 elevated, fine convolutions, radial ridges or 

 bumps, and a smooth area with radial 

 grooves gradually sloping into the submerged 

 margin. Surface moist -appearing and glossy. 

 Color of center apricot-orange to brown, 

 surrounded by an ochraceous-salmon or 



Figuke 64. Streptosporangium roseum (Reproduced from: Couch, J. N. J. Elisha Mitchell Sci 

 Soc. 71: 152, 1955). 



