154 ' BOTANICAL GAZETTE [February 



The small, ellipsoidal, uninucleated spores, 0.5-0.6X0.6- 

 o . 8 ju, are formed from close, sinistrorse spirals of 2-10 turns i . 2- 

 2 . 5 ju in diameter. Indications of septa can be seen only rarely. 

 The mature spore chains upon collapsing cohere in irregular 

 zoogloea-like masses, a peculiarity of behavior dependent probably 

 on a gelatinization of wall material. Upon germination, i or 2 

 tubes are produced, relatively thick and abundantly branching. 



Isolated 6 times from soil collected in Cambridge, Massachusetts. 



ACTINOMYCES IX 



Cultural characters. — On glucose agar, nutritive mycelium 

 colorless, forming no soluble pigment; aerial mycelium at first 

 white, becoming light smoky blue in the course of a few days. On 

 potato agar, cultural characters similar, but growth more profuse, 

 guttation moderate, discoloration of aerial mycelium more rapid; 

 tyrosinase reaction absent. 



Morphology. — -The most characteristic feature of this species 

 is the greater thickness of the fertile hyphae below the second turn 

 of the spiral. The latter are sinistrorse, usually with very close 

 turns, varying in number from i to 16, and measuring i .5-2.0 fx 

 in diameter. They give rise to ellipsoidal, uninucleated spores, 

 0.5-0.7X0.6-1.0 JU, without the appearance of clearly visible 

 septa. It seems highly probable that cross- walls nevertheless 

 occur, since occasionally a median partition may be differentiated 

 in the hyaline attentuated connections between two spores (fig. 51), 

 suggesting a development similar to that indicated in fig. 'joa-e. 



Isolated once from soil collected in Cambridge, Massachusetts. 



ACTINOMYCES X 



Streptothrix alba Rossi-Doria; Actinomyces griseus Krainsky (?) 



Cultural characters. — On glucose agar, growth poor and not 

 characteristic. On potato agar, growth excessively rapid, nutritive 

 mycelium colorless; aerial mycelium firm, white, changing rapidly 

 to a yellowish gray; secondary growth occurring in the formation 

 of numerous successive rings of sporodochia, or in the develop- 

 ment of cottony white masses of mycelium from below the thick 



