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Show 314 CEREAL PLANTS. CuAr. IX. diller in colotu 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 a.bscncc of barbs is a conspicuous difference, and in ccrta.in Gramincro serves even as a generic character; 27 although, as remarked by Godron/8 tho presence of barbs is variable in ccrta.in wild grasses, and especially in tho. c, such asJJromus sccalinus andLolium tenwlentnm, which habitually grow mingled with our cereal crops, and which have thus unintentionally been exposed to cultmc. Tho grains differ in size, weight, and coloru.·; 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 tcxtmc, being tender or hard, or even almost horny, and in the proportion of gluten which they conta.in. Nearly all the races or species of wheat vary, as Godron 20 has remarked, in an exactly parallel manner,-in tho seed being downy or glabrous, and in colour,-and in the florets being barbed or not barbed, &c. Those who believe that all tho kinds arc descended from a single wild species may account for this p~rallcl variation by the inheritance of a similar constitution, and a consequent tendency to vary in the same manner; and those who believe in tho general theory of descent with modification may extend this view to tho several sp~cics of wheat, if such ever existed in a state of nature. Although few of the varieties of wheat present any conspicuous difiercncc, their number is great. Dalbret cultivated during thirty years from 150 to 160 kinds, and excepting in tho quality of the grain they all kept true: Colonel Lo Coutcur possessed upwards of 150, and Plrilippar 3~2 varictics.30 As wheat is an annual, we thus see how strictly many trifling differences in character arc inherited thl'ough many generations. Colonel Lo Coutour insists strongly on this same fact: in his persevering and successful attempts to raise now varieties by selection, he began by choosing tho best oars, but soon found that tho grains in tho same car differed so that he was compelled to select them separately; and each grain generally transmitted its own character. The great amount of variability in tho plants of tho same variety is another interesting point, which would never have been detected except by an eye long practised to the work; thus Colonel Lc Coutour relates 31 that in a field of his own wheat, which he considered at least as pmo as that of any of his ncighboru. ·s, Professor La Gasca found twcnty-tlueo sorts; and Professor Honslow has observed simila.r facts. Besides such individual variations, forms sufficiently well marked to bo valued and to become widely cultivated 27 See an excellent review in Hooker's 'Journ. of llotany,' vol. viii. p. 82, note. 28 • Do l'Espcco,' tom. ii. p. 73. 20 Idem, tom. ii. p. 75. :!0 For Dalbret and Philippar, see I"oiselcur-Dcslongchamps, • Consid. sur lcs Ccrcalos,' pp. 45, 70. Lo Contour on Wlteat, p. G. ~ 1 'Varioti s of Wheat,' Introduction, p. vi. Marshall, in his 'Rural Economy of Yorkshire,' YOl. ii. p. D, remarks that "in every field of corn there is as much variety as in a herd of cattle." 315 Cuo~.I•. IX. WIIEAT. , 'ff h had the good fortune sometimes suddenly appear : thus Ml'. Shcn a~ t ivcly to raise in his lifetime seven new varieties, whiCh are now ox ons grown in many parts of Britain.32 • • ld and now As I·n the case of many other plants some vanctles, both 0 ' .arc far more consta.nt in character th' an others. c0 1~ no1 L 0 Coutct udr was forced to reject some of his new sub-varieties, which ~c suspcc 0 ha' d been produced from a cross, as m. corn·g i'b l Y SJ?Or ti vc. With. respecotr ntoe tho tendency to vary Metzger 33 gives from Ius own cxpcncncc s. interesting facts: ho d~soribes three Spanish sub-varieties, more c~pe~Iall~ one :known to be constant in Spain, which in Germany assumed thou P10P?I character only during hot summers; another variety kept true only m "'Ood land but after having been cultivated for twenty-five years became ~ore constant. He mentions two other sub-varieties which were at ~st inconstant, but subsequently became, apparently without any selectiOn, accustomed to their new homos, and retained their proper c~aractcr · These facts show what small changes in the conditions of lif~ cause variability, and they fmther show that a variety may beco~e hab~tuatc~ to new conditions. One is at fil'st inclined to conclude With .LmsolcurDcslongchamps, that wheat cultivated in the same country IS. exposed to remarkably uniform conditions; but manur~s differ, seed IS take~ from one soil to another, and what is far more unportant the plants are exposed as little as possible .to strugg~o. with other plants, and a~·o thus enabled to exist under diversified conclit10ns. In a state of natmo. cac~ plant is confined to that particular st~tio~ ~nd kind of nutriment which It can seize from the other plants by which It IS smrounded. . Wheat quickly assumes now habits of life. The summer an~ wmter kinds were classed by Linnams as distinct species; but M. Monrucr 34 has proved that the difference between them is only temporary. He sowed winter-wheat in spring, and out of one hundred plants four alone produced ripe seeds; these were sown and resown, and in three years plants v:cre reared which ripened all their seed. Conversely, nearly all the plants raised from summon-wheat, which was so>vn in autumn, perished fron: frost ; but a few wore saved and produced seed, and in three years this .s~mcrvaricty was converted into a winter-variety. Hence it is not sill'pnsmg that wheat soon becomes to a certain extent acclimatised, and that seed brought from distant countries and sown in Europe vegetates at first, or even for a considerable pcriod,35 differently from om Emopcan varieties. In Canada the fust settlers, according to Kalm,86 found their winters too severo for winter-wheat brought from France, and their summers often too short for summer-wheat; and until they procmed summer-wheat from t~e northern parts of Emopc, which succeeded well, they thought that their 3~ • Gardener's Chron. ancl Agricult. Gazette,' 18G2, p. DG3. aa • Getroidoartcn,' 1841, s. 66, 91, D2, 116, 117. 34 Quoted by Godron, 'Do l'Espcco,' vol. ii. p. 74. So it is, according to 1\Ietzgcr (' Getreidearten,' s. 18), with summer ancl winter barley. 3a LoiseleUl'-Deslongchamps, 'Cereales,' part ii. p. 224. Lc Coutcur, p. 70. 1\fn.uy other accounts could bo ac.ldod. BG 'Travels in North America,' 1753- l7Gl, Eng. translat., vol. iii. p. 165. |