174 The Roots of the Wheat Plant. 



comes apparent upon crushing the leaves of a young wheat plant 

 or leaves of the couch — triticum repens — in a peculiar disagreeable 

 odour, is, doubtless, derivable from the presence of an essential 

 oil, to which we may perhaps attribute the medicinal properties 

 which cause the emetic action on dogs ; and this unison of 

 quality in the herbage of wheat and the wild triticums would 

 at least lead to the inference of the affinity of the plants pro- 

 ducing it. 



Wheat has of late been decided upon as belonging to the genus 

 j^ffilops, perhaps all our forms having been produced from the 

 ^gilops ovata. Upon this subject a beautifully illustrated paper 

 will be found in the Royal Agricultural Society's Journal, with a 

 detailed account of the experiments by which the changes from 

 the wild grass to the cultivated wheat were produced by M. 

 Fabre. 



There can now, therefore, be no doubt as to the origin of our 

 cultivated cereal, and as the author of this Essay has the aegilops 

 in cultivation he would add that he sees no difficulty in receiving 

 M. Fabre's conclusions. 



These prefatory remarks have been made as concise as 

 possible consistently with tracing the botanical position and 

 origin of wheat. I shall, therefore, now proceed with more par- 

 ticular details in an essay on the development of the roots of 

 wheat in cultivation, adopting the following divisions, as pro- 

 posed by the Royal Agricultural Society, in the consideration of 

 the subject. 



1st. Characteristics of roots of autumn and spring sown 

 wheats. 



2nd. Acclimatization. 



3rd. Development to what extent affected by top-dressings 

 at various periods of growth. 



4th. Lifting action of frost, commonly called throwing out. 

 1. Characteristics of Roots, ^t. — In describing this subject it 

 will be well to point out the facts connected with seed-sowing- 

 and its progress in the following order : — 

 a. The preparation of the seed, 

 h. The processes connected with germination. 

 c. The after development of winter and spring wheat. 

 a. There is no plant more liable to attacks from epiphytes, 

 commonly called blights, than wheat, and experience has taught 

 the farmer that various chemicals — such as the caustic alkalisy 

 salts of copper, iron, and arsenic — if used as a pickle to the seed 

 previous to sowing, prevents blight; and this is attempted to be 

 explained upon the assumption that these matters kill the 

 sporules of the fungi, but my own experiments upon this subject, 

 together with careful investigation, seem to wari'ant the conclu- 



