314 



CEREAL PLANTS. Chap. IX. 



differ in colour and in shape, being quadrangular, compressed, or nearly 

 cylindrical ; and the florets differ in their approximation to each other, in 

 their pubescence, and in being more or less elongated. The presence or 

 absence of barbs is a conspicuous difference, and in certain Grammes 

 serves even as a generic character; 27 although, as remarked by Godron, 28 

 the presence of barbs is variable in certain wild grasses, and especially in 

 those, such as Bromus secalinus m&Ldium temulentum, which habitually grow 

 mingled with our cereal crops, and which have thus unintentionally been 

 exposed to culture. The grains differ in size, weight, and colour ; in being 

 more or less downy at one end, in being smooth or wrinkled, in being 

 either nearly globular, oval, or elongated ; and finally in internal texture, 

 being tender or hard, or even almost horny, and in the proportion of 

 gluten which they contain. 



Nearly all the races or species of wheat vary, as Godron 29 has remarked, 

 in an exactly parallel manner, — in the seed being downy or glabrous, and 

 in colour, — and in the florets being barbed or not barbed, &c. Those who 

 believe that all the kinds are descended from a single wild species may 

 account for this parallel variation by the inheritance of a similar consti- 

 tution, and -a consequent tendency to vary in the same manner; and 

 those who believe in the general theory of descent with modification may 

 extend this view to the several species of wheat, if such ever existed 

 in a state of nature. 



Although few of the varieties of wheat present any conspicuous differ- 

 ence, their number is great. Dalbret cultivated during thirty years from 

 150 to 160 kinds, and excepting in the quality of the grain they all kept 

 true : Colonel Le Couteur possessed upwards of 150, and Philippar 322 

 varieties. 30 As wheat is an annual, we thus see how strictly many trifling 

 differences in character are inherited through many generations. Colonel 

 Le Couteur insists strongly on this same fact: in his persevering and 

 successful attempts to raise new varieties by selection, he began by 

 choosing the best ears, but soon found that the grains in the same ear 

 differed so that he was compelled to select them separately; and each 

 grain generally transmitted its own character. The great amount of 

 variability in the plants of the same variety is another interesting point, 

 which would never have been detected except by an eye long practised 

 to the work; thus Colonel Le Couteur relates 31 that in a field of his own 

 wheat, which he considered at least as pure as that of any of his neigh- 

 bours, Professor La Gasca found twenty-three sorts ; and Professor Henslow 

 has observed similar facts. Besides such individual variations, forms 

 sufficiently well marked to be valued and to become widely cultivated 



27 See an excellent review in Hooker's on Wheat, p. G. 



' Journ. of Botany,' vol. viii. p. S2, note. 31 ' Varieties of Wheat,' Introduction, 



28 ' De l'Espece,' torn. ii. p. 73. p. vi. Marshall, in his ' Rural Economy 



29 Idem, torn. ii. p. 75. of Yorkshire,' vol. ii. p. 9, remarks that 



30 For Dalbret and Philippar, see " in every field of corn there is as much 

 Loiseleur-Deslongchamps, ' Consid. sur variety as in a herd of cattle." 



les Ce'reales,' pp. 45, 70. Le Couteur 



