The Myxomycetes of Eastern Iowa. hi 



CLASS ' MYXOMYCETES, Lin^. 



Chloroph3'l-less organisms whose vegetative phase consists 

 of a naked mass of protoplasm, the Plasmodium ; reproduced 

 by spores which are either free or enclosed in sporangia, and 

 which on germinating produce ciliated or amceboid zoospores 

 whose coalescence gives rise to the piasmodium. 



The Myxomjxetes are either: — 



A. Parasites in cells of living plants, Phytomyxix.e. 



B. Saprophytes, when they exhibit diverse plasmodia; 



a. Plasmodium of imperfectly united spores, . . . Acrasie/E. 



b. Plasmodium of spores completely blended, Myxogasteres.* 



Of these three sub-orders the Acrasiccp are the simplest, but 

 are so far unknown to our collection. 



ORDER PHl^TOMTXIX^, Schrater. 



The parasitic Myxomycetes include but few (four or five) 

 species, distributed among four genera. They are all ( r) para- 

 sites in the cells of living plants; their vegetativ^e phase is 

 plasmodial and their spores are formed by the simultaneous 

 breaking up of the piasmodium into an indefinite number of 

 independent cells. But a single genus need here concern us; 



PLASMODIOPHORA, Woronin. 



Parasitic in the parenchymatous cells of the roots of living 

 plants : causing noticeable enlargement of the affected organ, 

 producing at length galls, knots and various deformities and 

 distortions. Spores spherical, smooth, colorless, .016 mm. 



1 The term class is employed here for sake of symmetry. I have no quar- 

 rel with him. who prefers some other taxonomy. 



2 So Dr. J. Schroeter in Engler and Prantl's Natilrlichen Pflanzenfamilien: 

 Myxomycetes. The present systematic outline is substantially his, modified 

 to suit the present purpose. 



