96 CULTURE OF FARM CROPS. 



growth. Having thus described briefly the general habits 

 of growth of the wheat plant, it will be obvious that the 

 final and perfect development of the seed or fruit will be 

 dependent upon the way in which their habits are aided. 

 In the points involved in the discussion of the question as 

 to how the productive capabilities of wheat are dependent 

 upon the mode in which its habits of growth are consulted 

 and assisted by the modes of culture, Mr. Hallet, in a re- 

 cent paper in the ' Journal of the Royal Agricultural So- 

 ciety,' has some interesting and suggestive matter. Mr. 

 Hallet, by the term tillering, understands the " horizontal 

 development" of the roots; by the "vertical develop- 

 ment," the growth upwards of the leaves and stems ; and 

 by the " natural " growth of wheat, that mode of cultiva- 

 tion which gives free play to its nature, or by which the 

 habits of the plant as those we have already described 

 are best aided. The extent to which the "horizontal" 

 development takes place in the growth of the wheat plant 

 may be seen from the fact "that the stems of a single grain, 

 having perfect freedom of growth, will, in the spring, while 

 lying flat upon the surface, extend over a circle of 3 feet 

 in diameter, producing at harvest from fifty to sixty ears." 

 The vertical development is also dependent upon the way 

 in which the horizontal development is aided or retarded. 

 This, as Mr. Hallet points out, is abundantly shown by the 

 fact that thin crops generally produce fine ears. For de- 

 tails of great interest connected with the culture of wheat, 

 the reader is referred to Part I. of the present series on the 

 Culture of Farm Crops, chap, vi., p. 78, par. 49. 



CHAPTER SECOND. 



THE DISEASES OF WHEAT OP VEGETABLE ORIGIN RUST 



MILDEW SMUT, &C., &C. BURST, &C., &C. 



6. Classification of Diseases. It is impossible to over- 

 estimate the importance of a knowledge of the diseases 



