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Show 3UO ANOMALOUS MOD"8S CH,IP. XT. :.n·ison. Inn, h d of soocllings from 0. elon_qatnR, which grow non.r to?· pury1weus, n.nd was probably fortilisoJ by it, ~hrough tho ag~ncy of_ 1.n~~cts (for those, as I know by o:xporimont, pl~y an Important part m tho f01t~lis~~ tion of tho htblunum), tho sterile hylmJ G. pw'fiU?"eo-elouyattts appon.rod. Thus, also, w at01·or's laburnum, tho 0. al;rino-labw·numr s~ontauoously appeared, as I am informed by Mr. Waterer, in a_ b~d of scodlmgs .. On tho other hand, wo have a clear and d1stmct account gi~~n by l\f. Adam, who raised tho plant, to Poitoau/5 showing that 0. adam~ IS _not an ordinary hybrid. M. Aurtm inserted in tho usual mmmcr a sluold of tho bark of 0. purpm·eus into a stock of C. laburnum; and tuo bud lay dormant, as often happens, for a year; tho shield then ~roducod ~any buJs and shoots, one of which grew more upright and vigorous w1th larger leaves than tho shoots of 0. pwynweus, and was consequently propagated. Now it deserves especial notice that those plants wore sold by M. AJam, as a variety of o. pttqntreus, before they bad flowered; and the account was published by Poitoau after tho plants bad flowo~·od, but before they had exhibited their remarkable tendency to revert mto tho two parentspecies. So that thoro was no conceivable motive for falsification, an~ it is difficult to SOC ltOW thoro could haVO boon any OlTOr. If WO aJmit as true M. AJam's account, wo must admit tho extraordinary fact that two distinct species can unite by their cellular_ tissue, a~d s~bsoquontly produce a plant bearing loaves and sterile flowers mtm:modiato m char~ctor_botwccn tho scion and stock, and producing buds hablo to rovc~s10n; m ~hort, resembling in every important respect a hy~riJ formed m tho ordi~ary way by seminal reproduction. Such plants, If really thus formed, lllight be called graft-hybrids. I will now give all tho facts which I have been able to c~lloct _illustrative of tho above thoori s, not for tho sake of merely tluowmg llght on tho origin of 0. adumi, but to show in how many oxtmorJinary . ::mel comp!cx methods ono kind of plant may affect another, generally m connectiOn with bud-variation. 'l'ho supposition that either 0. lubumltm 01' zmrpur ·eus produced by orclin::try bucl-v::triation tho intermediate anJ tho other form, may, as alrco.Jy rcmarkcJ, uo absolutely excluded, from tho want of any evidence, from the groat amount of ch::tngc thus implied, 93 Brnun, in 'Dot. 1\Icm. Rny Soc.,' 18GB, p. xxiii. 9·& This hybrid has never been dcsrribcu. It ili exactly iutenncuiato in foliage, time of flowering. dark strim at tlw base of the standanl petal, lwirincs~ of tho ovarium, and in rtlmost every other character, between 0. laburnum and alpinus; but it approaches tho former species more nearly in colour, and exceeds it in tho length of the racemes. We have before soon that 20·3 per cont. of its pollen-grains are ill-formed and worthless. My plant, though growing not above thirty or forty yard~ from botlt ptLront-spccies, Lluring some sea~ons yioltlod no good s eds; but in 18GG it mts unusually fertile, and i tB long racemes prod uecd from one to OCC<tsionally oven four polls. Many of tho pods contained no good seeds, but generally they contained a single apparently good se d, sometimes two, aud in one case throe seeds. Some of tho seeds gorminutctl. 95 'Annalcs do la Soc. de llort. de Paris,' tom. vii., 18:10, p. 93. CHAP. XL OF REPRODUCTION AND V ARI.A.TION. 301 and from tho sterility of tho intermediate form. Nevertheless such cases as nectarines suddenly appearing on peach-trees, occasionally with tho fruit half-and-half in nature,-moss-roses appearing on other roses, with tho flowers divided into halves, or striped with different colours,-and other such cases, arc closely analogous in the result produced, though not in origin, with tho case of C. ctdarni. A distinguished botanist, Mr. G. H. Thwaites,96 has 1·ecordcd a remarkable case of a seed from Pttchsia coccinea fertilised by F. julgens, which contained two embryos, and was "a true vegetable twin." Tho two plants produced from the two embryos were" extremely different in appcamnco and character," though both resembled other hybrids of the same parentage produced at the same time. Those twin plants "were " closely coherent, below the two pairs of cotyledon-leaves, into a single " cylindrical stem, so that they had subsequently the appearance of being " branches on one trunk." Had tho two united stems grown up to their full height, instead of dying, a curiously mixed hybrid would have been produced; but even if some of the buds had subsequently reverted to both parent-forms, tho case, although more complex, would not have boon strictly anal?gous with that of 0. adami. On the other hand, a mongrel melon clcscnbod by Sagorot 97 perhaps did thus originate; for tho two main l!ranchcs, which arose from two cotyledon-buds, produced very different fruit,-on tho one branch like that of tho paternal variety, and on tho other brn.nc~ to a certain extent like that of the maternal variety, the melon of Cluna. Tho famous bizzat·ria Orange offers a strictly pamllel case to that of Oytisus adami. Tho gardener who in 1644 in Florence raised this tree, declared that it was a seedling which had been gmftocl; and after the gmft had perished, the stock sprouted and produced tho bizzarria. Gallosio, who carefully examined several living specimens and compared them with tho description given by tho original describer P. Nato,9s states that tho tree produces at tho same time leaves, flowers, and fruit, identical with tho bitter orange and with tho citron of Florence, and likewise compounJ fruit with the two kinds either blended together, both externally and internally, or segregated in various ways. This tree can be propagated by cuttings, and retains its clivorsifiod character. Tho so-called trifacial orange of Alexandria and Smyrna 99 resembles in its n-onorn.l nature tho bizzan:ia, hut differs fr~m it in the sweet oran,.e and citro~ being blended together m the same frUJt, and separately produced on the samo tree : nothi~g is kno~n _of its origin. In regard to tho bizzarria, many authors behove that 1t IS a graft-hybrid; Gn.llcsio on the other hanJ thinks that it is an ordinary hybrid, with tho habit of partially reverting 96 'Annals and 1\iag. of Nat. Flist.,' Mnrch, 18·18. 97 'Pomologio Physiolog.,' 1830, p. 126. ' 98 Gallesio, 'Gli Agrumi dci Giard. Dot. Agrar. di Fircnzu,' 1839, p. 11. In his' Traitc tlu Citrus,' 1811, p. 146, he speaks as if the compound fmit consisted in part of lemons, but this apparently was a mi~take. 99 'Card. Chron.,' 1855, p. 628. See also Prof. Caspary, in 'Transact. Hort. Congress of Amsterdam,' 1865. |