334 CEREAL PLANTS. Chap. IX. 



sent these heavier grains back to the South of France, but there 

 they immediately yielded lighter seed. 



All those who have closely attended to the subject insist on the 

 close adaptation of numerous varieties of wheat to various soils and 

 climates even within the same country ; thus Colonel Le Couteur 41 

 says, " It is the suitableness of each sort to each soil that will 

 enable the farmer to pay his rent by sowing one variety, where he 

 would be unable to do so by attempting to grow another of a 

 seemingly better sort." This may be in part due to each kind 

 becoming habituated to its conditions of life, as Metzger has shown 

 certainly occurs, but it is probably in main part due to innate 

 differences between the several varieties. 



Much has been written on the deterioration of wheat ; that the 

 quality of the flour, size of grain, time of flowering, and hardness, 

 may be modified by climate and soil, seems nearly certain; but 

 that the whole body of any one sub-variety ever becomes changed 

 into another and distinct sub- variety, there is no reason to believe. 

 What apparently does take place, according to Le Couteur, 42 is, that 

 some one sub-variety out of the many which may always be detected 

 in the same field is more prolific than the others, and gradually 

 supplants the variety which was first sown. 



With respect to the natural crossing of distinct varieties the 

 evidence is conflicting, but preponderates against its frequent occur- 

 rence. Many authors maintain that impregnation takes place in 

 the closed flower, but I am sure from my own observation that this 

 is not the case, at least with those varieties to which I have attended. 

 But as I shall have to discuss this subject in another work, it may 

 be here passed over. 



In conclusion, all authors admit that numerous varieties of 

 wheat have arisen ; but their differences are unimportant, 

 unless, indeed, some of the so-called species are ranked as 

 varieties. Those who believe that from four to seven wild 

 species of Triticum originally existed in nearly the same con- 

 dition as at present, rest their belief chiefly on the great 

 antiquity of the several forms. 43 It is an important fact, 

 which we have recently learnt from the admirable researches 

 of Heer, 44 that the inhabitants of Switzerland, even so early 



41 'On the Varieties of Wheat,' rity cannot be given (' Gard. Chron. 

 Introduct., p. vii. See Marshall, and Agricult. Gazette,' 1862, p. 

 ' Rural Econ. of Yorkshire,' vol. ii. p. 963), says, " I have never seen grain 

 9. With respect to similar cases of which has either been improved or 

 adaptation in the varieties of oats, see degenerated bv cultivation, so as to 

 some interesting papers in the ' Gar- convey the change to the succeeding 

 denei's Chron. and Agricult. Gazette,' crop. 



1850, pp. 204, 219. " ,3 Alph. De Candolle, « Geograph. 



42 'On the Varieties of Wheat,' p. Bot.,' p. 930. 



59. Mr. Shirreff, and a higher autho- 44 ' Planzen der Pfahlbauten, ' 188r>. 



