130 KANSAS UNIVERSITY QUARTERLY. 



the fibro-vascular bundles were only lightly held together. Thin 

 transverse sections reveal the bundles completely surrounded by the 

 masses of oospores, the parenchyma cells being entirely absent, and 

 only the fragile cuticle remaining to hold the bundles together and 

 preserve the shape of the mummified leaf. Neither the cuticle nor the 

 bundles are discolored. The parasite seems to have devoured the 

 parenchyma utterly, and to have incorporated it in its own rich mass 

 of oospores. 



Claviceps purpurea and a species of Fusisporium have been widely 

 spread in this locality for the past two years in Elymus Virginicus and 

 E. Canadensis. Both parasites occur in the young ovaries and cause 

 the complete destruction of their tissues. Even before the sclerotia 

 of Claviceps have emerged from the inner glumes, no vestiges remain 

 of the cell walls or cell contents of the ovaries. The presence of the 

 Fusisporitmi is manifested by the outgrowth, from between the glumes, 

 of a dark pink gelatinous mass. A section through a spikelet shows 

 the glumes bound together by the growth of a dense mycelium and the 

 tissues of the ovary almost or entirely replaced by the fungus. (In 

 one section some fragments of the starch-bearing cells remained, but 

 no starch grains.) Excepting the occasional discoloration of the cells 

 contiguous to the fungus, the glumes do not seem to suffer. The 

 spores, which are obscurely septate and curved-fusiform, are borne 

 chiefly by that portion of the fungus which has replaced the ovary. 

 Frequently the Fusisporium occurs in the same spikelet as the Clavi- 

 ceps, and then the pink gelatinous mass growing about and up the 

 dark sclerotium produces a striking contrast. 



With reference to their effect upon their hosts, the parasites on 

 grasses embraced in these notes may be grouped as follows : 



1. Those not preeminently destructive to tissues already formed, 

 but which appropriate to themselves the currents of elaborated sap, 

 and the nutrition of the whole plant suffers in consequence. The 

 Puccinias are examples. 



2. Those that produce abnormal outgrowths from the plant, in 

 which to develop their spores. In this class all parts of the host 

 suffer from the appropriation by the parasite of the elaborated sap, 

 and frequently a normal growing point is caused to produce abnormal 

 tissues, so that the proper development of fruit or foliage is interfered 

 with. Ustilago Zece-Md^ys is an example of this class. 



3. Those that attack the chlorophyll bearing tissues of the host, 

 and disintegrate and feed upon their cells. In this class the nutrition 

 of the host is curtailed by the destruction of a part of its elaborating 

 tissues. Piricularia grisea belongs to this class. 



4. Those that attack the developing ovaries, destroying their 



