CHYTRIDIALES 435 



nomidae (midges), Ephemerida (mayflies), Phryganeidae, Sparrow (loc. 

 tit., pi. 1, figs. 17-18, pi. 4, figs. D-F), mayflies, Sparrow (1943: 295), 

 chitin, from moist soil, Karling (1948c: 509), exuviae of various aquatic 

 insects, Sparrow (1952d: 768), United States; chitin, Karling (1945c: 

 362), Brazil; exuviae, Canter (1953: 290), Great Britain. 



Details of the morphology and development of the species are given 

 by Sparrow (1937a); and by Antikajian (1949: 245), based on Karling's 

 material (see also "Cytology," p. 92). The occurrence of sexuality has 

 been observed in a number of instances by the present writer. The 

 process differs in no essential features from that in Siphonaria, although 

 the tenuity of the rhizoids and the smallness of the contributing thallus 

 often make examination and interpretation extremely difficult. Anti- 

 kajian (1949), however, was unable to confirm the presence of sexuality. 

 Inasmuch as Haskins (1950) noted in Diplophlyctis sexualis and Karling 

 (1945d) in S. petersenii that resting spores may be either sexually or 

 asexually formed, it is apparent that a similar situation exists in Aster- 

 ophlyctis. 



Antikajian (1949) determined that, predominantly, the sporangium 

 develops, as had previously been noted by other investigators, from the 

 expanded body of the zoospore. In some instances, however, the nucleus 

 of the encysted germinated zoospore passes out and the germ tube and 

 the nucleated part enlarge to become the sporangium; the more distal 

 portion then elongates and forms the rudiments of the rhizoids. The 

 region of union of the primary rhizoidal branches then expands to form 

 an apophysis. Rarely, the apophysis is absent. She at first cultivated the 

 fungus on a 2 per cent chitin agar, but later found the chitin to be non- 

 essential, the plants growing equally well on a peptone, yeast extract, 

 dextrose, agar medium. 



A form with a nearly spherical sporangium covered by small solid 

 bipartite spines assigned to this species by Sparrow (1937a: pi. 1, fig. 19) 

 has been identified with Phlyctochytrium aureliae by Ajello (1945). 



RHIZOPHLYCTIS A. Fischer 



Rabenhorst. Kryptogamen-FL, 1 (4): 119. 1892 (sensu recent. Minden, Kryp- 

 togamenfl. Mark Brandenburg, 5: 374. 1911 [1915]) 

 (Fig. 28 A-D, p. 440) 

 Karlingia Johanson, Amer. J. Bot., 31 : 397. 1944. 



