A NEW BALANSIA ON CYPERUS 



C. W. Edgerton 

 (With Plate 12) 



During the summer of 191 7, an interesting species of Balansia 

 was found attacking the fruiting parts of Cyperus virens. The 

 fungus seemed to be of special interest as the described species 

 of this genus are mostly listed as occurring on grasses. The 

 region in which the specimens were found consisted of a low 

 swampy sedge meadow in which Cyperus virens made up a con- 

 siderable portion of the plant population. A large portion of the 

 sedge plants of this species were attacked by the fungus. The 

 fungus formed large black sclerotia in place of the fruiting parts, 

 and as Cyperus virens is one of the very large sedges, diseased 

 plants were very conspicuous. Specimens in all stages of de- 

 velopment were found in abundance. 



Cyperus virens develops in large stools often with fifteen to 

 twenty or more flower stalks and it was interesting to note that 

 a stool was either entirely healthy or else all of the flower stalks 

 were diseased. Although a careful search was made, no stools 

 were found which contained both healthy and diseased flower 

 clusters. This held true eyen though the stools were touching 

 each other or were interlaced. This seemed to show that the in- 

 fection must have occurred very early in the development of the 

 host plant or else the mycelium of the fungus was perennial. 



The fungus is easily demonstrated in the very young flower 

 buds. The young bud which would normally develop into a 

 whole flower cluster is at first enclosed by the large leaves. A 

 bud from a diseased stool has the appearance of being perfectly 

 healthy, yet a cross section shows the mycelium to be abundant 

 between the different parts. The host cells, however, do not 

 appear to be injured in these very small buds. Buds were ex- 

 amined that were less than two millimeters in diameter. 



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