THK GENUS N0CARD1 I 



25 



Table I 

 Summary oj growth characteristics of t8 strains of Nocardia (McClung, 1949) 



Set (Miliary 



branching 



I ragmen tat ion 



\ ■ 



Type 1 



I 



Type 3 



( rroup I 



\Y F 



.V. aquosus 



KI..I 



15 B 



N. erythropolis . . 



X . polychromogt nes 

 (Ik. up II 



L3-20 



13-8 



N. ruber 



.Y. polychromogenes 



N. astt roides 



Group III 



21 3 



13-10 



L8-2 



13 15 



13 3 



20-6 



13 

 12 

 13 



11 

 11 

 11 



1!) 

 is 

 20 

 120 

 96 



40 50 



30 65 



Unknown 



1 'ills now n 



McClung (1949) divided the genus Nocar- 

 dia into three groups: 



I. Scant mycelial development, sparse 

 branching. Colonial texture soft, pasty, 

 and sometimes mucoid; pigment intra- 

 cellular and insoluble. 

 II. Extensive mycelial development, 

 straight branches which do not over- 

 lap. Colonial texture soft and pasty; 

 pigment intracellular and insoluble. 

 III. Extensive mycelial development, no 

 fragmentation of hypliae, contorted and 

 profusely produced branches which 

 overlap. Colonial texture waxy or 

 cartilaginous; generally both intracel- 

 lular and soluble pigments are pro- 

 duced ( Figs. 8, 9). 

 The pattern in Nocardia fragmentation 

 can he separated into three types. In Type 

 1, ao acute angle is formed in a hypha pre- 

 ceding division, which occurs at the apex of 



the bend; following division the new hypha] 

 tips giow out parallel to each other. In Type 

 2, division occurs in a straighl or slightly 

 curved portion of a hypha; following di- 

 vision, the newly formed ends bend slightly 

 and grow past each other. In Type 3, di- 

 vision occurs in the parent hypha close to or 

 at the juncture of a branch; a new hypha 

 may grow from the place of division at 

 the base of the branch; the newly formed 

 hypha) tip bends and continues to grow. 

 Type 1 fragmentation is characteristic of 

 Group I, and Type :! of ('.roup II. Type 2 

 occurs in both groups, and Group III lack- 

 fragmentation (Fig. 10). 



A summary of the growth characteristics 

 of various strains of Nocardia belonging to 

 these three groups is presented in Table l. 



In an attempt to find a group of depend- 

 able properties for the separation of the 

 genera Nocardia, Streptomyces, and Myco- 



