568 AQUATIC PHYCOMYCETES 



ENDOCHYTRIUM Sparrow 



Amer. J. Bot. : 20: 71. 1933 



(Fig. 34 A-E, p. 571) 



Thallus endobiotic, monocentric, eucarpic, mono- or polyphagous, 

 consisting of the rudiment of the sporangium and the branched rhizoid- 

 al system emerging from it, the cyst and penetration tube evanescent 

 or persistent; sporangium operculate, with a discharge tube the tip of 

 which at least is extramatrical ; zoospores formed in the sporangium, 

 posteriorly uniflagellate, with a single globule; resting spore thick-walled, 

 endobiotic, borne like the sporangium, apparently asexually formed, 

 upon germination functioning as a prosporangium, the sporangium 

 epibiotic, operculate. 



The species are weakly parasitic or saprophytic in fresh-water green 

 algae or saprophytic in decaying plant tissues. 



Morphologically, the genus is the operculate counterpart of Ento- 

 phlyctis. 



KEY TO THE SPECIES OF ENDOCHYTRIUM 



Sporangia predominantly ovoid or pyriform, smooth 



Resting spore filling container; case of the infecting zoospore not 

 persistent 



Resting spore entirely smooth-walled E. ramosum, p. 568 



Resting spore warty E. operculatum, p. 569 



Resting spore lying loosely in the container, the outer wall scaly; case 



of the infecting zoospore persistent E. pseudodistomum, p. 570 



Sporangia predominantly elongate, obclavate, or triangular and bas- 



ally lobed, often somewhat apophysate E. digitatum, p. 572 



Endochytrium ramosum Sparrow 



Amer. J. Bot., 20: 72, pi. 2, figs. A-G. 1933 



(Fig. 34 A-E, p. 571) 



Sporangium ovoid, subspherical, or sometimes pyriform, up to 35 \i 

 in diameter, with a short broad discharge tube which just penetrates 

 the wall of the substratum, wall thm, smooth, colorless; rhizoids ex- 

 tensive, irregularly and profusely branched, ramifying through many 

 cells, often broad (up to 10 [x in diameter) at the basal or somewhat 



