CHYTRIDIALES 393 



The first fungus, a keratinophilic form, differs markedly from the 

 type in that the sporangium does not arise by vesiculation of the dorsal 

 side of the rhizoid but, typically (as in Entophlyctis), from the germ 

 tube. Karling (1946e) had originally applied the binomial Perirhi- 

 za endogena n.g., n.sp., to this fungus, without descriptions. Later 

 (1947a), he considered it tentatively a species of Phlyctorhiza. Further 

 study (1951a) of material, from Israeli soil, which he considered to be 

 P. variabilis, indicated that it had, in contrast to his original isolate, 

 a strong tendency for polycentricity. He presents convincing evidence 

 that the predominantly monocentric strains and the strongly polycentric 

 one are actually the same organism and concludes, from this and other 

 morphological evidence, that they are more closely related to Catenaria 

 (of the Blastocladiales). Since, however, data on their sexuality, resting- 

 spore formation, germination, and so forth, are as yet unavailable, he 

 retains the fungus in the Chytridiales. 



The second one, Sparrow's Cuban fungus, in which polycentricity 

 is very rare and a discharge tube is lacking, appears more nearly to 

 agree with the concept of Phlyctorhiza. There is some evidence that 

 the sporangia arise by vesiculation of the rhizoids, but this is not 

 certain. It is, therefore, kept as a questionable member of the genus 

 until further observations are made. 



Probably both Karling's and Sparrow's fungi should be removed 

 from Phlyctorhiza. 



? Phlyctorhiza variabilis Karling 

 Amer. J. Bot., 34: 27, figs. 1-43. 1947 



Perirhiza endogena Karling, nom. mid., Amer. J. Bot., 33, suppl. no. 3, 

 p. 219. 1946. 



"Thallus eucarpic, monocentric [or polycentric], 1 usually wholly 

 intramatrical. Sporangia variable in size and shape; spherical (8-70 u,), 

 oval (6-30 x 8-50 \l), oblong, narrowly or broadly fusiform (10-15 

 X 14-45 \x), pyriform, obpyriform, irregular, angular, or somewhat 

 stellate, with one, rarely two or three exit tubes, 4—10 ^ wide by 10-90 \i 



1 In the light of Karling's (1951a) study, "or polycentric" has been substituted 

 for the "rarely polycentric" of the original description. 



