i6 



Journal of Agricultural Research 



Vol. XX, No. i 



the surface of the host or remain endophytic, 150 to 250 by 100 to 250 m- Peridium 

 smooth and small-celled at the basal part, but large-celled, verrucose occasionally, 

 with protuberance-like projections of cell groups near the apical end, black to the 

 unaided eye (turning red-brown with acid reaction), dark blue with transmitted light 

 except the almost colorless often rather prominent beak; asci up to over a hundred 

 in each perithecium, intermixed with a few celled paraphyses; ascospores, 8 in one row 

 or irregularly in two rows, subdorsi ventral, fusiform, slightly curved, tapering at the 

 ends, ochreous in masses; largely 3-septate, 20 to 30 by 3.75 to 4.25 /u (up to 5 n in 

 diameter in germination, indicated by constrictions at the septa). 



Conidial stage. — In shape the conidia (fig. 1) strongly resemble the 

 conidia of Fusarium culmorum. but they lack the constriction toward the 



base so prominent in F. culmorum. 

 They differ also in being longer and 

 more slender and in having thinner 

 walls and less prominent septa; coni- 

 dia typically, sometimes up to 100 per 

 cent, 5-septate, 45 to 65 fj. by 4.2 to 

 5.5 m; 3-septate, 35 to 45 u by 5 to 5.5 

 n; seldom 4-septate; rarely 6-, 7-, or 

 more septate, 60 to 75 n by 4 to 5 /x; 

 ochreous in mass. Chlamy dospores 

 absent. Carmine red pigment on 

 starchy, neutral media. 



Habitat. — This species is one of the 

 most widely distributed species of 

 Fusarium within the temperate zone, 

 causing headblight and rootrot of 

 wheat, emmer, rye, oats, spelt, and 

 corn in the United States, Germany, 

 Russia, Italy, Denmark, Sweden, and 

 probably elsewhere. Wollenweber iso- 

 lated it from berries of Solatium tuber- 

 osum near Berlin, Germany. C. A. 

 Ludwig isolated the same from Ipomoea batatas in storage at La 

 Fayette, Ind. The writer found the perithecia of the fungus on 

 Bromus, timothy stems, clover, and alfalfa, and also on Triticum repens 

 which had been plowed under. The fungus was also isolated from aspara- 

 gus stems collected at Baraboo, Wis., by Mr. E. H. Toole. According to 

 Saccardo (6, p. 313), the fungus occurs on dead stems of Angelica, Aspar- 

 agus, Beta, Clematis, Conium, Cannabis, Convolvulus, Cucurbita, Gyn- 

 eria, Phytolacca, Scirpus, and Stipa, and on branches of Buxus, Coronilla, 

 Fraxinus, Gleditschia, Juglans, Robinia, Rubus, Rosa, and Ulmus 

 in Europe, Algeria, North America, and Australia. A. D. Selby (10) 

 adds Emmer, Trifolium, and Medicago as new hosts. It has been found 

 also on Glyceria aquatica in Germany, on rice in Japan and Italy, and on 

 Triticum spclta in S. Paulo, Brazil. 



Fig. i. — Conidia of Gibberella saubinelii. 



