:;i 1 



THE ACTINOMYCETES, Vol. II 



sporangium in water brings about the swell- 

 ing of an intersporal substance, causing 

 the wall and the spores to push out on one 

 side, forming a cone-shaped projection 

 about half as long as the diameter of the 

 sporangium. The spores are forcibly ejected 

 through an opening in the cone. They are 

 noninotile, spherical, 1.8 to 2.0 n in diameter, 

 with one shiny globule. Sporangia] wall is 

 persistent for several hours after spore 

 discharge. In addition to sporangia, spores 

 are also formed in coils somewhat as in 

 Streptomyces, though the coils are much less 

 conspicuous (Fig. 65). 



Sucrose nitrate agar: Colony usually flat, 

 level with agar surface; concentric zonation 

 distinct or absent. Surface glossy or powdery. 

 Color usually white, sometimes pinkish- 

 buff or cream-buff. Sporangia absent to 

 fairly abundant, always formed some dis- 

 tance above the surface of the agar. In some 

 cultures, coils form which break up into 

 spores as in Streptomyces. 



Glucose-asparagine agar: Growth poor, 

 slightly elevated and minutely ridged, slop- 

 ing to the fimbriate margin. Surface of 

 central region powdery with white aerial 

 hyphae. Sporangia absent. 



Potato-glucose agar: Growth usually good, 

 center elevated with irregular bumps and 



ridges; margin flat and even with surface of 

 agar. Color of colony at first creamy, be- 

 coming tawny and then brown, after which 

 white floccose spots of hyphae appear, 

 usually spreading to cover the entire culture. 

 Sporangia usually formed in vast numbers, 

 the white areas becoming rosy pink as the 

 sporangia mature; the pinkish areas are 

 frequently minutely pocked. Surface moist 

 at first, appearing dry and floccose as aerial 

 hyphae and sporangia are formed. Agar 

 colored reddish-brown with a vinaceous 

 tinge. 



Nutrient agar: Growth fair, color usually 

 cream-buff, rarely buff-brown. Surface usu- 

 ally glossy, sometimes powdery with aerial 

 hyphae which may be united to form many 

 upright fascicles. Sporangia absent. 



Habitat: Garden soil in North Carolina 

 and forest litter in Holland and Denmark 

 (Van Brummelen and Went, 1957). 



Remarks: Nonomura and Ohara (1960b) 

 found the genus Streptosporangium widely 

 distributed in the soils of Japan. In addition 

 to the original S. roseum Couch, four new 

 species were isolated: S. a/hum, S. iiridial- 

 bwn, S. amethystogenes, and S. vulgare. These 

 were classified on the basis of the color of 

 the aerial mycelium and formation of soluble 

 pigment on oatmeal agar media. 



