CHYTRIDIALES 233 



On chytrids 



Rhizoidal system tubular with short, lateral, 

 stubby extensions; on Phlyctochytrium 



aureliae R. chytriophagum, p. 248 



Rhizoidal system slender, with delicate taper- 

 ing branches 



On Chytriomyces R. chytriomycetis, p. 248 



On Rhizophlyctis (Karlingia) and Septochy- 



trium R. hyperparasiticum, p. 248 



On spores of higher plants (pollen, etc.) 

 Sporangium spherical; pores sessile 



Resting spores not observed R. sphaerotheca, p. 249 

 Resting spores quickly and abundantly formed, 



wall beset with bullations R. bullatum, p. 250 

 Sporangium angular, the apices terminating in 



pores R. racemosum, p. 251 



On plant debris; sporangium surrounded by one to 



several hyaline zones or "halos" R. coronum, p. 251 

 On animals or material of animal origin 



On cysts of Vampyrella ; sporangium with several 



subapical discharge papillae R. vampyrellae, p. 252 

 On Amoeba and insect exuviae; sporangium with 



one apical discharge papilla . . . R. amoebae, p. 253 



On chitinous substrata R. chitinophilum, p. 253 



Typical sporangium small (6-12 \j. in diameter); 

 zoospores few 



On filaments of Vaucheria R. constantineani, p. 254 



On Asterionella; resting spore smooth 



R. planktonicum, p. 254 

 On Rhizophlyctis; resting spore bullate 



R. marshallense, p. 255 

 Sporangium wall deliquescing upon or after discharge 

 of zoospores ; on algae 

 On the green alga Sphaerocystis R. sphaerocystidis, p. 255 

 On the desmids Staurastrum and Arthr ode sinus 



R. difficile, p. 256 

 On diatoms 



Wall completely deliquescing and releasing 

 zoospores 



On Cyclotella R. cyclotellae, p. 257 



On Melosira R. melosirae, p. 258 



On Achnanthes R. achnanthis, p. 258 



Wall deliquescing only after zoospores have es- 

 caped through one to three discharge pores ; 

 on Fragilaria R. fragilariae, p. 259 



