OCR Text |
Show 301 ANOMALOUS MODES CuAl.'. xr. scgr gation. vVhcn, however, the later flowers or fruit, proc1ncccl during tho same season or during a succeeding year or generation, become striped or half-in-half, &c., tho segregation of the two colours is strictly a case of rev rsion by bud-variation. In a futuro chapter I shall show that, with animals of crossed parentage, the same individual has Leon known to change its character during growtb, and to revert to one of its parents which it did not at first resemble. :From tl1e various facts now given there can be no doubt that tho same individual plant, whether a· hybrid or a mongrel, sometimes returns in its leaves, flowers, and fruit, either wholly or by segments, to both parentforms, in tho same manner as tho Gytisus adami, and the Bizzan·ia Omnge. We will now consider the few facts which have been recorded in support of the Lelicf that a variety when rrrafted or budded on another variety sometimes aff~cts the whole stock, OL' at tho poiut of junction gives rise to a bud, or graft-hybrid, whieh partakes of the characters of both stock and scion. It is notorious that when the variegated J cssaminc is budded on tlto common kind, tho stock sometimes produces buds beaTing vm·icgatcd leaves: 1\ir. Hivcrs, as he informs me, has seen instances of this. The same thillg occuxs with the Olcandcr.110 J\ir. Rivers, on tho authority of a trustworthy friend, states that some buds of a golucn-varicgatcd ash, which were in ci-ted into common ashes, all died cxc pt one; but tho ashstocks •vcrc aJfcctcd,111 and produced, both above and below the point!:; of insertion of the plates of bark bearing tho dead buds, shoots which l>oro variegated leaves. 1\'Ir. J. Anderson IIcmy bas commmucatcd to mo a nearly similar case : 1\fr. Brown, of Perth, observed many years ngo, in a Highland glen, an ash-tree with yellow leaves; and buds taken from this tree wore inserted into common ashes, which in consequence were afl'cctod, and produced the .lJlotched JJreadalbane .Ash. Thi · variety has boon propagated, and has preserved its character during the last fifty y ars. Weeping ashes, also, were budded on the afl'cctcd stocks, and became similarly varil:!gatcd.. l\fany authors consider variegation as the r csnlt of dis ase; and on this view, which however is doubtful, for some variegated plants arc perfectly healthy and vigorous, the foregoing cases may be looked at as the direct result of the inoeulation of a disease. Variegation is much influenced, as we shall hereafter sec, by the natuxc of the soil in which the 11o Gartner (' Bustanlcrzcugung,' s. 611) give!! many rcfercnctts .on this subject. Ill A ncruly similar account was given by llradlcy, in 1724, in l1i~ ''l'n.ati~e on Husbanury,' vol. i. p. l9D. CllAI'. XI. OF REPRODUCTION AND VARIATIO~. 3!)5 ~lants arc grown; and it docs not seem improbable that whatever chango m the sap or tissues certain soi ls induce, whether or not called a disease might spread from the inserted piece of bark to tho stock. But a chang~ of this kind cannot be considered to bo of the nature of a graft-hybrid. 'l'hcre is a variety of the hazel with dark-puxplo leaves, like those of tho copper-beech: no one has attributed this coloux to disease, and it apparently is only an exaggeration of a tint which may often be seen on tho leaves of the common hazel. When this variety is grafted on tho common hazcJ,Il2 it sometimes colours, as has been asserted tho leaves below the graft; but I should add that Mr. Hivers, who ha~ possessed hunurcds of such grafted trees, has never seen an instance. Gartner 113 quotes two separate accounts of branches of clark and whitcfruit? d ':'incs which had. ?con Ullitcd in various ways, such as being split longitudinally, and then Jomcd, &c. ; and these branches produced distinct lmnchcs of grapes of the two colom·s, and other bunches with grapes either striped or of an intermediate and now tint. Even the leaves in one case were variegated. 'l'heso facts arc tho more remarkable because An~row.Knight never succeeded in raising variegated grapes by fertilising wlutc kmds by pollen of dark kinds; thouo-h, as we have seen, he obtaiuod sccdline;s with variegated fruit and leaves, by fertilising a white variety by tho variegated dark Aleppo grape. Gartner attributes the above-quoted cases merely to bud-variation; but it is a strange coincidence that tho branches which had been grafted in a peculiar manner should alone have thus varied; and II. Adorno de •rscharncr positively asserts th.at ho produced the described result more than once, and could do so at w1ll, by splitting and uniting the branches in the manner described by him. I should not have quoted the following case had not the author of 'Des J acinthcs ' 111 impressed me with the belief not only of his extensive knowledge, but of his truthfulness: he says that bulbs of blue and red hyacinths ma.y be cut in two, and that they will grow together and throw up a muted stem (and this I have myself seen), with flowers of the two colours o~ the opposite sides. nut the remarkable point is, that flowers arc sometimes prouuccd with the two colouxs blcmlcd together, which makes tho case closely analogous with that of the blended colouxs of the grapes on tho united vino-l.Jranchcs. 1\ir. R ~rail s~atcu in 1867, before the Botanical Society of Edinburgh (and ha~ smcc g1vcn me fuller information), that scvcml years ago he cut about Sixty blue an.d.whitc potatoes into halves tlll'ough the eyes or buds, and then carefully JOmcd them, destroying at the same time the other eyes. Som~ o.f these unit cl tubers produced white, and others blue tubers; and 1t IS probable that in these cases the one half alone of the bud grew. Some, l:owovcr, produced tubers partly white and partly blue; and tho tubers from about foux or five wc1·c regularly mottled with the two colours. In these latter cases we may conclude that a stem had been formed by 112 Louuon's 'Arboretum,' vol. iv. p. 25D5. 113 • Ba~tnrdcrzcugung,' s. G1 D. 114 Amsteruaro, 1768, p. 12-.L |