151 DISEASES OF WHEAT. 



DISEASES OF WHEAT. 



Wheat or Smut Brand (Uredo sitophila, Dittmar). Among all the species of brand 

 which infest our grain crops, this is by far the most worthy of notice. It lodges only in 

 the ears of wheat, and is found in no other kind of grain or grass. It migrates with wheat 

 in all climates of the earth, without being subject to local influences, as is almost ever the 

 case with the other cultivated plants. The farmer dreads it most, and justly; for being 

 lodged in the ears when they are brought to be threshed, it is there dispersed by the flail 

 or threshing machine, and thus directly infects the sound grain ; while the barley and oat 

 brands are for the most part out on the field, and hence the largest portion of the seed of 

 these latter ki:ds of brand necessarily falls on meadow, forest, or other kinds of soil, which 

 are not applied to the cultivation of grain, and so, for the want of plants adapted to the 

 infection, are not further spread. 



Those halms of wheat which afterwards bear ears affected with brand, may be early 

 distinguished, before their bloom, by their luxuriant growth and their dark green color, as 

 well as by their large, broad, stiff" leaves. They apparently bloom much earlier; but very 

 often (yet not always) their anthers contain no grains of pollen (powder of fructification) ; 

 and the first act of fructification, the shedding of their pollen on the cup of the pistil, is 

 very imperfect; and should the ears affected by the brand and already diseased be dusted 

 with sound pollen, the little balls of pollen usually form no aggregation of pollen on the 

 pistil, or such as are formed do not press into the pistil and down to the ovary. The 

 fructification of the blossoms of wheat affected by brand is therefore imperfect ; and in case 

 the grains of pollen form no cluster in the cup, then there is indeed no fructification ; but 

 the careful observer finds on almost all the ears ripe for receiving the grains of brand, on 

 the side of every seed corn affected with brand, one or two anthers (Plate LV, fig. 3, 4, 

 6, b) , which, on the buds which are well fructified and bear seed, the anthers with their 

 stamens have long since fallen off. The anthers which remain standing on the grains 

 affected with brand are usually destitute of pollen; and sometimes we find that the same, 

 in consequence of efforts at imperfect fructification, are stuck, as it were (fig. 4, b, right side) , 

 to the pistils which remain standing (fig. 4, c) . The two pistils which remain standing, 

 of the seed affected with brand, are usually covered and joined together by delicate white 

 threads interwoven like mould in a sort of network (Plate LV, fig. 4, c) . This mould 

 formation belongs essentially to the wheat brand, and forms as it were a part of the root 

 texture of the fungus constituting the brand. It always exists, only frequently more or 

 less developed, and therefore more or less easily found. It wholly covers the head of the 

 seed, and lies between the chaff-hairs (fig. 16, h) , while the sound seed exhibits not a 

 trace of such an interwoven fibrous formation among the chaff-hairs on its head. The 

 same is also the case in respect to the pistils of the sound seed (fig. 16, i) . With the 

 development of this outer fibrous mould begins likewise the transformation of the seed, as 

 well in respect to its external form as to its internal structure. 



