CHYTRIDIALES 391 



wall about 2 \x thick surrounding the contents, in which are many oil 

 globules of approximately the same size, and a spherical apophysis 

 5-7 [x in diameter, at germination functioning as a prosporangium. 

 Saprophytic in cells of Cladophora sp. {he. cit.), Nitella sp., Sparrow 

 (1952d: 767), United States; Chara sp., vegetable debris, Richards 

 (1951 : 487, figs. 1-19, pi. 24), Great Britain; substratum? plant tissue, 

 Ookubo (1954: 58, fig. 46), Japan. 



PHLYCTORHIZA Hanson 



Amer. J. Bot., 33:732. 1946 



(Fig. 24 E-G, p. 396) 



"Thallus monocentric, eucarpic, intramatrical. Zoosporangia de- 

 veloping as an outgrowth of the germ tube while the zoospore usually 

 persists as a cyst. Rhizoidal system oriented on the base and periphery 

 of the sporangium, frequently anastomosing. Zoosporangia variously 

 shaped, with one basal, lateral, or apical exit papilla. Zoospores pos- 

 teriorly uniflagellate. Resting spores variously shaped, thick walled, and 

 apparently developing in the same manner as the sporangia; upon 

 germination functioning as prosporangia" (Hanson, he. cit.). 



On insect integuments. 



The account of development in Phlyctorhiza endogena is adapted from 

 Hanson (1946). Upon germination the zoospore forms a stout germ 

 tube, which penetrates the basement membrane of the integument and 

 develops short irregular branches. Thalli are dorsiventrally differen- 

 tiated, with the dorsal surface Rhizophlyetis-like, but not the ventral, 

 which is traversed by rhizoids. The sporangial rudiment is believed to 

 begin as a unilateral vesiculation of an incipient rhizoid. It becomes a 

 thin flattened extension between the branches. The thalli strikingly 

 resemble a bat's wing or duck's foot, with the sporangia corresponding 

 to the web, the ventral parts of the rhizoids to the digits. 



As the rhizoids grow out radially (more or less in one plane) the 

 layers of the integument are spread apart. Vesiculation continues along 

 the paths opened up in the substratum and the incipient sporangia are 

 irregular or sometimes stellate in surface view. After vesiculation ceases 

 the sporangia expand and become more regular, often circular, in 



