978 MANUAL OF DETERMINATIVE BACTERIOLOGY 



Genus II. Micromonospora ^rskov. 



(0rskov, Investigations into the morphology of the ray fungi. Copenhagen, 1923, 

 147; inchides Thermoactinomyces Tsilinsky, Ann. Inst. Past., 13, 1899, 501; ibid., 

 17, 1903, 206.) 



Well developed, fine, non-septate mycelium, 0.3 to 0.6 micron in diameter. Grow 

 well into the substrate. Not forming at any time a true aerial mycelium. Multiply 

 by means of conidia, produced singly at end of special conidiophores, on surface of 

 substrate mycelium. Conidiophores short and either simple, branched or produced 

 in clusters. Strongly proteolytic and diastatic. Many are thermophilic and can 

 grow at 65°C. Usually saprophytes. These organisms occur mostly in hot composted 

 manure, dust, soil and in lake bottoms. 



The type species is Micromonospora chalcca (Foulerton) 0rskov. 



Key to the species of genus Micromonospora {0rskov Group III). 



I. Vigorously growing organisms, typically with copious spore formation on glucose- 

 asparagine-agar. 



A. Vegetative mycelium pale pink to deep orange, no typical soluble pigment. 



1. Micromonospora chalcea. 



B. Vegetative mycelium orange changing to brownish-black, brown soluble 



pigment. 



2. Micromonospora fusca. 



II. Slowly and feebly growing organisms, with scant spore formation on glucose- 

 asparagine-agar, no soluble pigment. 



A. Vegetative mycelium pale pink to pale orange. 



3. Micromonospora parva. 



B. Vegetative mj^celium yellow to orange-red. 



4. Micromonospora globosa. 



C. Vegetative mycelium blue. 



5. Micromonospora vulgaris. 



Note : This genus could be subdivided on the basis of the relations of the organisms 

 to temperature, since it includes a number of thermophilic forms which grow readily 

 at 55° to 65°C, mesophilic forms having their optimum temperature at 30°C, and 

 organisms growing at low temperatures in lakes. Each of these can be divided into 

 3 groups, based on the structure of the spore-bearing hyphae. Among the thermo- 

 philic forms, only representatives of the first group have so far been isolated in pure 

 culture although the existence of the other two groups has definitely been demon- 

 strated in microscopic preparations. These are: 



Group 1. Simple spore-bearing h^yphae. 



Group 2. Branching spore-bearing hyphae. 



Group 3. Spore-bearing hyphae in clusters. 



1. Micromonospora chalcea (Fouler- Bact., 1927, 221.) From Greek chalceus, 



ton) 0rskov. (Streptothrix chalcea Foul- bronze. 



erton, Lancet, 1, 1905, 1200; Nocardia Description from Jensen, Proc. Linn. 



chalcea Chalmers and Christopherson, Soc. New So. Wales, 57, 1932, 173. 



Ann. Trop. Med. and Parasit., 10, 1916, Formation of a unicellular mycelium 



268; 0rskov, Thesis, Copenhagen, 1923, which forms distally placed, singly situ- 



156; Actiiioinj/ccs chalcca Ford, Tcxtb. of ated spores. No aerial hyphae. No sur- 



