354 
Journal of Agricultural Research 
Vol. XXV, No. 8 
be seen by the following measurements of asci and ascospores found upon 
three different hosts. 
Asci (m)- Ascospores (m)- 
Wheat. 75.0 to 105.0X10.5 to 13.5 60.0 to 90.0X3-0 to 3.5 
Chaetochloa . 80.0 to 100.0X10.2 to 13.0 61.0 to 87.0X3.0 to 3.5 
Festuca . 85.0 to 100. oX 10. o to 13.0 61.0 to 88.0X3-0 to 3.5 
These measurements are also in close agreement with those given by 
Fitzpatrick, Thomas, and Kirby (4). As these authors have not considered 
the species of Ophiobolus previously described which is found on wild 
grasses in this country, it seems desirable to present briefly the data ob¬ 
tained by the senior author on this phase of the subject. 6 Of the species 
of Ophiobolus that have been described as occurring on wild grasses the 
following deserve consideration: O. Andropogonis E- & E., and O. Festucae 
Tracy and Earle. Through the kindness of Dr. F. J. Seaver of the New 
York Botanical Garden type material of O. Andropogonis was carefully ex¬ 
amined and compared with Arkansas material. As far as measurements 
of asci and ascospores are concerned, Ellis and Everhart's (3) species 
might readily be taken for underdeveloped material of O. cariceti , but 
the perithecia with large beakless osteoles, the absence of any blackish 
mycelium on the host tissue in which the perithecia are buried, and the 
apparent saprophytic nature of the fungus, are sufficient to mark it as 
distinct. Examination of co-type material of O, Festucae Tracy and 
Earle (13) found in the Missouri Botanical Garden shows two different 
fungi present, but the one, doubtless, which was described possesses asci 
and ascospores very much like those to be found in Ophiobolus species. 
However, the perithecia instead of being beaked or papillate, open by 
means of a cleft in the host epidermis. The fungus belongs to the genus 
Lophodermium and perhaps is close to L. arundinaceum (Schrod.) Chev. 
var. alpinum Rehm. Other species of Ophiobolus which have been 
considered, but which, judging from the descriptions, are very different 
from O. cariceti axe : O. eucryptus (B. & Br.) Sacc., O. leptospermus (Speg.) 
Sacc., O, trichisporus E- & E-, O. medusae E. & E-, O. paludosus (Feltg .) 
Sacc. & D. Sacc., O. herpotrichus (Fr.) Sacc., O, coffeatus {Berk,) Sacc., 
O. stictisporus (Cook & Ellis) Sacc., O. littoralis (Crouan) Sacc., O. cut - 
morum (Crouan) Sacc., and O. helicosporus (B. & Br.) Sacc. 
PATHOGENICITY" OF OPHIOBOLUS 
As all the field observations suggested that Ophiobolus attacked weak, 
poorly growing plants, it seemed worth while to test the effect of different 
fertilizers in a field where Ophiobolus was present. For this purpose 4 
acres of the field in which Ophiobolus existed were set aside by Mr. Pool 
for our use. The 4 acres chosen consisted of two areas of similar size, 
one in the southeast comer and the other in the northwest comer of the 
field. These parts were selected because wheat attacked by Ophiobolus 
had been found to be most abundant on them and the fungus appeared 
equally distributed throughout. The chosen areas were divided into 
1-acre plots, each of which received the following: Plot 1, no treatment; 
plot 2, 10 tons of manure; plot 3, 1 ton of burnt lime; plot 4, 400 pounds 
of commercial fertilizer of a 4-8-3 formula. The manure, lime, and 
commercial fertilizer, with the exception of sodium nitrate, which was 
applied the following March, were disked in at the same time, in the fall, 
and all the plots otherwise received the same treatment throughout. 
• We are indebted to Dr. E. A. Burt for the use of the splendid library and mycological herbarium of the 
Missouri Botanical Garden. 
