CHYTRIDIALES 405 



Main rhizoidal axis predominantly short, occasionally some- 

 what expanded; resting spores always sexually formed by 



rhizoidal anastomosis Siphonaria, p. 423 



Sporangium wall spiny, deliquescing, save for the base, at spore 



discharge Solutoparies, p. 426 



Rhizoidal system arising from a thick-walled, cuplike basal portion 

 of the sporangium or from an apophysis or from several places 

 on the sporangium 



Rhizoids arising from a cuplike basal portion, or apophysis 

 Rhizoids arising from a thick-walled cuplike basal portion 



of the sporangium Obelidium, p. 427 



Rhizoids arising from an apophysis 



Sporangium spherical Rhizoclosmatium, p. 431 



Sporangium irregularly lobed, distinctly stellate 



ASTEROPHLYCTIS, p. 433 



Rhizoids arising from several places on surface of sporangium 

 Sporangium wall persistent after spore discharge; zoospores 



swimming away individually Rhizophlyctis, p. 435 



Sporangium wall dissolving at zoospore discharge; zoospores 

 escaping as a free-swimming aggregate which disassociates 

 into successively smaller groups and, ultimately, into in- 

 dividuals Nowakowskia, p. 448 



Body of encysted zoospore forming the rudiment of a prosporangium 

 or a germ tube which expands in part to produce a prosporangium; 

 resting spore resulting from the conjugation either of adnate thalli, 

 in which case developed in the receptive thallus, or budded from 

 the fused thalli, or from thalli joined by a tube and formed in the 



tube Subfamily Polyphagoideae, p. 449 



Body of encysted zoospore enlarging into rudiment of prosporan- 

 gium 

 Zoospores escaping from the sporangium through an apical ori- 

 fice as free-swimming bodies: resting spore formed in the con- 

 jugation tube Polyphagus, p. 449 



Zoospores escaping from the sporangium through a subapical or 

 lateral orifice as nonmotile or motile bodies or germinating 

 in the sporangium ; resting spore formed by the receptive thal- 

 lus, conjugating thalli adnate Sporophlyctis, p. 456 



Body of encysted zoospore producing a germ tube, part of which 



expands to form the prosporangium Endocoenobium, p. 459 



SUBFAM. RHIZIDIOIDEAE 

 Reproductive rudiment formed from the body of the encysted 

 zoospore or aplanospore; rhizoids arising directly from the body of the 



