326 AQUATIC PHYCOMYCETES 



Sporangium spherical, broadly ovoid, or ovate 



Teeth upright, shallowly cleft P. zygnematis, p. 341 



Teeth cleft nearly to base, slightly divergent 



P. magnum, p. 342 

 Sporangium cylindrical or ovoid, or broadly ovate, teeth 

 upright or converging, deeply cleft 

 Sporangium cylindrical or ovoid, teeth converging 



P. dentation, p. 343 

 Sporangium broadly cylindrical or broadly ovate, 

 with a rounded or flattened base, teeth upright 



P. quadricorne, p. 343 

 Teeth forming two whorls around the discharge papilla, the 

 outer whorl containing six teeth, the inner, four 

 Outer whorl of teeth borne at the top of large flangelike 



solid bosses, inner whorl sessile P. bullatum, p. 344 



Outer and inner whorls of teeth sessile 



Sporangium predominantly cylindrical and slightly 



expanded distally P. urceolare, p. 345 



Sporangium subspherical or ovoid . . P. dentifcrum, p. 346 



Phlyctochytrium hydrodictyi (Braun) Schroeter 



Engler and Prantl, Naturlichen Pflanzenfam., 1 (1): 78. 1892 (1893) 



Chytridium hydrodictyi Braun, Monatsber. Berlin Akad., 1855: 383; Ab- 

 handl. Berlin Akad., 1855: 52, pi. 4, figs. 20-25. 1856. 



Phlyctidium hydrodictyi (Braun) Rabenhorst, Flora Europaea algarum, 

 3:279. 1868. 



Rhizidium hydrodictyi (Braun) Fischer, Rabenhorst. Kryptogamen-Fl., 1 

 (4): 108. 1892. 



Sporangium sessile, short-ovoid or pyriform, with a rounded apex, 

 5-25 [i in diameter by 15-33 u. high, wall thin, smooth, colorless; 

 endobiotic part consisting of a spherical subsporangial swelling about 

 5 [x in diameter, apparently without rhizoids ; zoospores spherical, 

 3 (j. in diameter, with a single globule, uniflagellate, escaping fully 

 formed through an apical pore; resting spore not observed. 



On diseased cells of Hydrodictyon utriculatum, Braun, Frantzius (in 

 Braun, 1856a: 53), Bail (1855: 682), Rabenhorst {he. cit.), Germany; 

 Hydrodictyon reticulatum, de Wildeman (1891: 171), Belgium; Hydro- 

 dictyon reticulation, Valkanov (1931a: 363), Bulgaria; Rhizoclonium 

 hieroglyphicum, Sparrow (1932b: 277, fig. 2c), United States. 



