GRASSES OF IOWA. 207 



The Septoria tritici Desm. is closely related to the above and 

 should perhaps be regarded as nothing more than a variable 

 form of S. graminum. The spots it produces are at first yellow, 

 then reddish-brown, and finally whitish. The spores are 50- 

 60" long by 1.5" to 2" wide and usually divided. A Septoria 

 has been reported on the glumes of wheat in Ohio by Selby.* 



Several other species of Septoria are allied to the above 

 species, one, the Septoria bromi Sacc. is common in this state 

 on Bromus secalinus. 



CLADOSPORIUM HERBARUM (PERS.) LINK. 



This fungus is destructive in parts of Australia, and has been 

 reported on the increase in Europs by FrankJ, it also occurs 

 in this country as reported by Peck. The writer has likewise 

 observed it on wheat arid oats in Iowa. Harvey reported it on 

 oats in Maine. On wheat it is commonly referred to as blight. 

 It attacks all parts of the plant but is especially common in the 

 heads. The mycelium of the fungus grows not only on the sur- 

 face of the plant but also in the interior. The conidiophores 

 and spores are olive green. The conidiophores pass through 

 the siomata or break through the epidermis. The spores are 

 one to two-celled and are borne on the end or on short lateral 

 branches. The spores are extremely variable in shape and 

 size. 



The general effect of the disease is to cause the kern< Is to 

 shrivel. The disease occurs rather destructively on oats as 

 recorded by Cobb. § Professor Peck|| records the occurrence 

 of a Cladosporium on oats, which he describes as a new species, 

 the Fusicladium destruens. He says in regard to oats. "The 

 foliage of the plants presented a singular admixture of green, 

 dead-brown and reddish hues, strongly suggestive of that of a 

 'rust- struck' field. " Peck thinks this fungus inhabits the leaves 

 of some of our northern grasses and has escaped from them to 

 oat fields. Mr. P. C. Stewart made a study of Cladosporium 

 while at Ames, finding it on many wild grasses, especially blue 

 grass. Giltayl reports that plants are infected in the same 

 way as in some of the grain smuts, the spores being carried 



♦Bull. Ohio Agrl. Exp. Sta. 97: 42. 

 tOobb. 3: 991. 



tUeber die Befallung durch Cladosporium und Phoma. Zelt. f , Pflanzenk. 3: 28. Rep. 

 Maine State Coll. 1894; 96. /. 3. 

 iOobb. 3: lOOO. 



IIRep. N. Y. state Mus. of Nat. Hist. 43: 9 pi. 3.f. 19.22. 1890. 

 lUeber die Schwarze des Getreldes. Zelt. f. Pflanzenk. 3: 200. 



