676 AQUATIC PHYCOMYCETES 



Allomyces moniliformis Coker and Braxton 



J. Elisha Mitchell Sci. Soc, 42: 139, pi. 10. 1926. Emend. Emerson, Myco- 



logia, 30: 127. 1938 

 (Fig. 40 F-G, p. 616) 



Basal cell up to 150 \x or more in length by 17-48 u. in diameter, 

 hyphae tapering, 12-18 \i in diameter, slightly but distinctly constricted 

 at the pseudosepta, dichotomously branched, the pseudocells up to 655 ;x 

 long, contents in old cultures becoming slightly pink ; primary sporangia 

 narrowly clavate or cylindrical, 62-135 u. long by 20-32 [i in greatest 

 diameter, with an apical papilla, secondary sporangia formed predom- 

 inantly in basipetal succession, ovoid to nearly spherical, with truncate 

 ends and from one to four lateral papillae, successively diminishing in 

 size, the proximal ones as small as 20 u, in diameter, contents pink, 

 becoming browner as the zoospores approach maturity ; zoospores ovoid, 

 10-15 [a long by 5-8 \x broad, with a long posterior flagellum, capable 

 of repeated emergence; resting spores narrowly to broadly ovoid, with 

 truncate base and pronounced apical beak, usually 43 75 \i long by 

 21-43 \i in greatest width, generally slipping out of their containers at 

 maturity, the exospore thick-walled, dark orange-brown, with widely 

 spaced pits, germination of the Cystogenes type, primary bifiagellate 

 planonts and cysts 11-15 \i in diameter, isogamous gametes from the 

 cysts 8-9 fj. in mean diameter. 



In moist sand and loam, Coker and Braxton (he. cit.), United 

 States; Mexico; Cuba; Puerto Rico (doubtful); Trinidad; Bolivia. 



Allomyces moniliformis is unique because it is the only member of the 

 genus to have carotinoid pigment in structures other than the male 

 gamete. Emerson (1938a) established the occurrence of cyst formation 

 in the species, using an isolate obtained from J. N. Couch. Although 

 not the type isolate, this was probably the one Teter (1944) compared 

 with Sparrow's Trinidad strain. In general aspect, Sparrow's strain, 

 which Teter studied carefully, is similar to Couch's A. moniliformis. 

 The Trinidad strain is alone, however, of any of the Blastocladiales, in 

 having all motile bodies devoid of flagella; movement is amoeboid only. 

 By running parallel cultures with the North Carolina strain, Teter proved 

 that this was not merely due to environment. The North Carolina 

 isolate always bore flagellate bodies whereas the Trinidad strain never 



