61 

 showed abvoidant evidence of infaction in several days. In the field, in- 

 fected heads are not foimd for several days aftev the sclerotia germinate. 

 They are first noticed about the early part of June, about 24 days after 

 germinating sclerotia are first found. Diseased heads becorce very common 

 during July, especially if June has been rainy. 



The infecting ftoigus attacks the pistil of the grass flower, 

 and in a few days the ovary is almost entirely destroyed, a mass of fungus 

 tissue filling the space it occupied. On the surface of the fungous growth, 

 there are numerous tufts of hyphae standing at right angles to the central 

 rsass. Each tuft contains a number of hyphae. The digital ends of these 

 hyphae, or certain of them, enlarge and form conidia. The conidia are 

 hyaline but show granules when stained, oblong, about Sp, wide and 15|i long. 

 Th^ are produced in great abundance and are carried from Mxe hyphae on 

 v/hich they were produced by a droplet of Honey dew. 



The sphacelia stage in which honey dew is esoided lasts but 

 a few days. In some cases within a week after the sphacelia stage reaches 

 its height the young sclerotia 1 to 2 millimeters in diameter are projecting 

 from between the glumes of the spikelets. They continue to grow until 

 some reach a diameter of about 4 mm. The sclerotium of £. nasisali has very 

 marked poisonous properties. 



£.• tihilipnii Rehm (209) 



Stronata gregaria, e Sclerotic 2-2 l/2 cm, longo, -3 mm. lat., 

 subcylindrico onata, capitata, subglofeosa, scabra, stipitata, cum 

 Sclerotic nigerrima, Capitula superficie peritheciis immersis exasperata, 

 0,3-1.0 ma diam. stipite c.l mm. alt., 0.2-0.5 mm, lat, intus albida, firma 

 Peritbeoia iimersa, minima, oculo nonarmato vix perspicua. Asci creberrimi, 

 clylinracei, apice rotundati et incrassati, 120-150|j, Ig., 6tj, lat. 8 spori. 

 Sporidia filiformia, recta, 1 cellularia, subflavidula, parallele posita. 



