122 Blight in the Cereals. [Sept., 



nally in the fruit buds of onts, and afterwards more or less wholly 

 attacks the other parts of the bloom. The outer skin of the fruit 

 buds is destroyed extremely quick, and soon is entirely gone, and 

 before the ears are fully developed the blossom and fruit organs 

 are destroyed even to the outer and inner leaves of the bud (Fig. 

 24), and the shedding of the pollen of the brand-spores has 

 then commenced. The diseased ears of oats show them at a dis- 

 tance by their stunted spikes and little branches. The fungous 

 brand itself in a ripe state forms a brownish black extremely soft 

 powder, which very rapidly sheds out, and examined by the mi- 

 croscope, consists of very small transparent roundish little grains, 

 which viewed under the water (Fig. 25) are globular or elongat- 

 ed, very often for a time double, and of unequal form and size. 

 Viewed (h-y or without water (Fig. 26) they still appear in simi- 

 lar forms, but then they are folded over or with curved hollows. 

 They consist of a very delicate single spore-skin, and a spore-ker- 

 nel almost slimy, filling the whole spore-skin. The spores them- 

 selves are very minute; their diameter in the round spores are 

 0.000270 ( 3,^3 ) Paris inch, and the longest diameter of the 

 elongated ones only 0.000310 ( 3 aVe ) Paris inch. They are 

 twice or three times less than the little grains of the wheat brand, 

 and much smaller than the spores of the barley brand which are 

 represented in the plate, and from the latter of which they are dis- 

 tinguished sufRciently in the structure of the spore-kernel. This 

 species of brand resembles the millet brand as little as it does the 

 barley, as the general structure and spores of that brand are both 

 perfectly distinguishable, only the oat brand, the barley brand, and 

 the millet brand have smooth spores, though indeed with difficul- 

 ty to be confounded and compared; the other kinds of brand which 

 have their abode in the buds of our grasses have spores with 

 grained spore-skin, and on this account can neither be confounded 

 nor compared. The oat brand scatters itself early in the field, and 

 it is highly probable, that the spores of all the kinds of brand al- 

 ready shedding their dust on the field remain for years in the soil, 

 retaining their germinating power until their mother plants again 

 come under cultivation there, or that they sow themselves in the 

 yet tender and first ripening seeds of plants in their neighborhood, 

 and thus already lay the germ for the development of their pro- 

 geny. 



Explanatio7i of the Illustrations. 

 Plate I, Fig. 23, an ear of oats afTected with brand, natural 

 size. Fig, 24, a single fruit bud of the same diseased. Fig. 

 25, spores of the oat brand represented under water and strongly 

 magnified. Fig. 26, the same examined dry and powerfully 

 magnified. 



