CHYTRIDIALES 



103 



C. tenue Nowak. (Fig, 35), can be included with certainty. This 

 species differs from those of Physoderma and Urophlyctis in its 

 failure to form resting spores and in forming its sporangia from 

 enlargements of the mycelium. It has been found in Europe 

 in the tissues of various marsh plants (Acorns, Iris, etc.), and in 



Fig. 34. — Caienaria anguillidac Sorokin (a) Young thallus developed from 

 swarmspore. (6) Mature thallus with swarmsporangia and delicate terminal 

 branches, (c) Swarmsporangium freeing swarmspores. {After Dangeard.) 



the slime which often covers their submerged surfaces. Other 

 species doubtfully included in the genus are C. polystomum Zopf, 

 C cornutum De Wildeman, and C. irregulare De Wildeman. 



5. Physoderma Wallroth, (Flora Crypt. Germ., 2 : 192, 1833). 



In this genus and in Urophlyctis all the species are parasitic 

 in the tissues of higher plants. Resting spores are always present 



Fig. 35. — Cladochytrium tenue Nowakowski, showing mycelium, swarmsporan- 

 gia, and swarmspores. {After Nowakowski 1876.) 



and abundant. Sporangia have been found in only a few species, 

 and when formed are epiphytic and develop directly from the 

 swarmspore instead of from the mycelial enlargements. In these 

 cases [P. maculare Wallr., P. butomi Schrot., U. pidposa (Wallr.) 

 Schrot.], the mycelium attached to the sporangium is limited in 

 extent, monophagus, and similar in appearance to that of Rhizo- 

 phidium of the preceding family. Other swarmspores infecting 



