BLASTOCLADIALES 663 



the zoosporangial plants but smaller, averaging 106 u. on peptone agar, 

 the + or — gametes similar to the zoospores but smaller; zygote 

 biflagellate and germinating at once to form a sporophyte. 

 In soil, coll. Ulmcke, Mexico. 



Blastocladiella variabilis Harder and Sorgel 



Deutsch-Dominik. Tropenforschungsinstituts, Hamburg-Ciudad Trujillo 



D.S.D., 1: 123. 1939 



(Fig. 39, p. 612) 



Rhopalomyces variabilis Harder and Sorgel, Nachrichten Gesell. Wiss. 

 Gottingen, Math.-Physik. Kl., Fachgruppe VI (Biol.) (N.F.), 3(5): 123, 

 figs. 1-3, fig. 4 B-E. 1938. 



Basal cell cylindrical, holdfasts delicate, much branched, wall thin, 

 smooth; sporangium clavate, colorless, wall chitinous, thin, smooth, with 

 several discharge papillae; zoospores ovoid, with a refractive saddle- 

 shaped "food body" and a long posterior flagellum; resting spore borne 

 like the sporangium, spherical, with a thick dark-brown several-layered 

 wall (sculptured?), cracking upon germination and allowing papillae to 

 protrude, which upon dissolution form pores for the escape of numerous 

 posteriorly uniflagellated planonts; planonts upon germination giving 

 rise to thalli that resemble the zoosporangial plants, on each of which 

 is produced either a colorless or an orange-colored clavate gametangium 

 (+ or — ); gametes isogamous (+ or --) fusing in pairs to form a 

 zygote, which at once produces a sporophyte plant. 



Saprophytic in soil, coll. Ulmcke, Dominican Republic. 



By analogy with long-cycled species of Allomyces the pigmented 

 gametangium could be regarded as the male and the colorless one as 

 the female. 



Blastocladiella cystogena Couch and Whiffen 

 Amer. Journ. Bot., 29: 589, figs. 1-14, 49-57, 58-63. 1942 



"Zoosporangial thalli lacking in life cycle. Resting sporangial thalli 

 when on leaves usually extramatrical, spherical or pyriform and sessile 

 or with a very small and inconspicuous stalk, frequently intramatrical 

 on leaves and then subspherical ovoid or lobed; on hemp seed usually 



