596 AQUATIC PHYCOMYCETES 



and three to six minute refractive globules; emerging fully formed and 

 lying quiescent for a few moments in a globular mass at the exit orifice 

 before swimming away; intermittently amoeboid. Resting spores inter- 

 calary, oval, 30-50 x 50-75 \i, spherical, 25-115 u., amber, and yellow 

 to light-brown in color, smooth or covered with coarse, simple or 

 branched pegs or filamentous extensions, 4-18 \jl long; wall 4-6 y. thick, 

 content coarsely granular with one to several large refractive granules; 

 germination unknown" (Karling, he. cit.). 



Saprophytic in vegetable debris, Karling (he. cit.; 1942c: 620; 1948c: 

 510), United States. 



This species is left in Septochytrium, as is S. marilandicum, with grave 

 misgivings since it is only rarely septate. It might better be regarded as 

 a species of Nowakowskiella. The ornamented resting spores are sus- 

 pected by Karling to possibly be encysted sporangia bearing abortive 

 rhizoids. 



MEGACHYTRIUM Sparrow 

 Occ. Papers Boston Soc. Nat. Hist.., 8:9. 1931 ; Amer. J. Bot., 20: 73. 1933 



(Fig. 37 A-B, p. 598) 



Thallus epi- and endobiotic, strongly polycentric, eucarpic, consisting 

 of much-branched broad tubular occasionally septate hypha-like fil- 

 aments bearing at frequent intervals the swollen rudiments of the 

 sporangia or resting spores; sporangia operculate, intercalary or borne 

 at the tips of short lateral branches; zoospores posteriorly uniflagellate, 

 with a single globule, formed in the sporangium; resting spore thick- 

 walled, usually intercalary, contents with globules, upon germination 

 functioning as a prosporangium and forming externally an operculate 

 zoosporangium. 



A monotypic genus, found thus far only on Elodea. 



By reason of its tubular polycentric vegetative system the genus 

 represents a chytridiaceous counterpart of the anteriorly uniflagellate 

 Hyphochytr ium. The complete development of the thallus is not known. 

 Because of the opaque character of the host difficulty was encountered 

 in tracing it. The zoospore upon germination gives rise to a rather broad 

 undulating "hypha" which, as it grows over the host surface, expands and 



