316 CEREAL PLANTS. Chap. IJ. 



country was useless for corn crops. It is notorious that the proportion of 

 gluten differs much under different climates. The weight of the grain 

 is also quickly affected by climate : Loiseleur-Deslongchamps 37 sowed near 

 Paris 54 varieties, obtained from the South of France and from the Black 

 Sea, and o2 of these yielded seed from 10 to 40 per cent, heavier than the 

 parent-seed. He then sent these heavier grains back to the South of 

 France but there they immediately yielded lighter seed. 



Al 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 Coutenr" 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 

 m 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 gram, time of flowering, and hardiness 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 Coutenr » 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 occurrence. Many 

 authors maintain that impregnation takes place in the closed flower, but I 

 am sure from my own observations 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. 40 It is an important fact, 

 which we have recently learnt from the admirable researches 



37 ' Cereales,' part ii. pp. 179-183. Mr. Sheriff, and a higher authority 



38 'On the Varieties of Wheat,' Intro- cannot be given ('Gard. Chron. and 



duct., p. vii. See Marshall, 'Kural Agricult. Gazette,' 1862, p. 963), says, 



Econ. of Yorkshire,' vol. ii. p. 9. With "I have never seen grain which has. 



respect to similar cases of adaptation in either been improved or degenerated 



the varieties of oats, see some interesting by cultivation, so as to convey the 



papers in the ' Gardener's Chron. and change to the succeeding crop." 



Agricult. Gazette,' 1850, pp. 204, 219. *> Alph. De Candolle, ■ Geograph.. 



39 ' On the Varieties of Wheat,' p. 59. Bot.,' p. 930. 



