ADDENDA 567 



(Halst), is mentioned on p. 413 as occurring in the United 

 States on cultivated celery, has recently appeared in epidemic 

 form on celery in this country. In some cases, large, 

 scattered, and isolated spots are formed on the leaf, which 

 remain dark brown, and become studded with the perithecia 

 of the fungus. In other instances, the greater portion or 

 the whole of the leaf becomes studded with small blackish 

 patches, on which the perithecia are crowded. 



Perithecia immersed, globose or ovoid, glabrous, blackish- 

 olive, ostiolum minute, not at all prominent, conidia broadly 

 elliptical, hyaline, 5-7 x 3-4 fi. 



Indian corn mildew. In the United States, maize, Indian 

 corn, or corn, is frequently attacked by two closely allied 

 species of fungi. The disease affects the ear, showing as a 

 whitish mould, spreading over the surface of the grain, 

 sometimes covering the whole ear, at other times localised 

 in patches. The amount of mildew present on the surface 

 of the grain is scanty, but upon breaking the ear the spaces 

 between the bases of the grains are seen to be densely packed 

 with a mass of snow-white mycelium. Numerous minute 

 black specks of the fruit of the fungus may be found 

 embedded in the mycelium situated at the point of attach- 

 ment of the grain to the cob ; such fruit is not produced on 

 the superficial mycelium. These fruits may belong either to 

 Diplodia macrospora (Earle) or to Diplodia maydis (Sacc). 



D. maydis, perithecia gregarious, black, beak conico-acute, 

 conidia elliptic-cylindrical, sometimes clavulate, straight or 

 curved, i-septate, scarcely constricted, coloured, 25-30x6 \i. 



Stevens and Hall, who have paid special attention to this 

 disease, state that the damage is placed at from 10 to 50, 

 to 75 per cent, of the value of the crop. Both species of 

 Diplodia live on corn stalks, and the fungus multiplies on 

 such old stalks. It is consequently most important to plough 

 under all old stalks, leaves and shucks, so as to secure future 

 crops from infection. 



Stevens, F. L., and Hall, J. G., Rep. N.C. Agric. Exp/. 

 S/a., 1907-08, p. 37. 



Monkey-nut leaf blotch. This plant, Arachis hypogea, 

 known in the West Indies as 'earth nut,' and in the United 

 States as 'peanut,' is often severely injured by Cercospora 

 persona/a (Ellis), which forms numerous more or less circular 



