86 THE LOWER FUNGI— PHYCOMYCETES 



aspect of the open sorus of swarmsporangia. This latter charac- 

 teristic led earlier investigators to mistake these fungi for rusts. 

 In fact several species were first described in Aecidium and 

 Uredo. 



The common North American representative of the genus, 

 W. aecidioidcs (Peck) Sydow, was first described by Peck in the 

 genus Uredo. It was later placed in Synchytrium by Farlow, and 

 will be most frequently encountered in the literature under the 

 name S. decipiens Farlow. The species occurs in America on the 

 hog peanut, Amphicarpa monoica and A. pitcheri, and in Oriental 

 India and Japan on A. edgeworthii. It is probably the best known 

 representative of the Chytridiales in the United States. It has 

 been studied cytologically by Harper (1899), Stevens (1903; 

 1907), and Griggs (1908; 1909 a, b, c). The infecting swarm- 

 spore is uninucleate, and the uninucleate condition is main- 

 tained in the developing thallus until it approaches maturity. 

 This nucleus, termed the primary nucleus, enlarges rapidly as the 

 thallus grows, and finally attains an extraordinary size. It then 

 divides to form nuclei for the sporangia, and these in turn, after 

 the sporangial walls are initiated, divide to provide nuclei for the 

 swarmspores. The species forms galls on the leaves, stems, 

 and other aerial portions of the host, and may sometimes be 

 found even on the fleshy subterranean pods of the lower flowers. 

 The species is clearly very closely related to W. puerariae (Henn- 

 ings) Sydow occurring in the Far East on Pueraria. 



Kusano (1909: 86, 112) studied the latter species very critically, 

 and found the swarmspores to be uniciliate. He, consequently, 

 followed the nomenclature of Miyabe (1905: 199) who had first 

 placed the species in Synchytrium. Later Ito and Homma 

 (1926) confirmed this finding, and demonstrated that the swarm- 

 spores are uniciliate in W. aecidioides also. Since these two 

 species fail to show the swarmspore character described for 

 Woroninella, and since the open powdery nature of the sorus is 

 not typical of Synchytrium they erected a new genus Miyabella 

 Ito and Homma for them. 



The following year Gaumann (1927) examined the type species 

 of Woroninella, W. psophocarpi, and proved that in it also the 

 swarmspores are uniciliate. There is no longer, therefore, any 

 reason for retaining the genus Woroninella. Nevertheless, since 

 the group of species here treated differ from the other known 

 species of Synchytrium in the strikingly powdery aspect of their 



