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Show 330 UULIN AU.Y PLANTS. CIIAI'.!X. years, which always came true. From tho analogy of kidney-beans I should have expected 80 that occasionally, perhaps at long intervals of time, when some slight degree of sterility had supervened from long-continued self-fertilisation, varieties thus growing ncar each other woul<l have crossed; and I shall give in the eleventh chapter two cases of di tinct varieties which spontaneously intcrcrosscd, as shown (in a manner hereafter to be xplaincd) hy th pollen of tho one variety havino- acted directly on tho seeds of tho other. Whether the incessant supply of new varieties is pftrtly dno to . uch occasional and accidental crosses, and tl10ir fleeting existence to changes of fashion; or again, whether the varieties which arise after n. long course of continued self-fertilisation arc weakly :m<L soon p rish, I cannot oven conjecture. It may, however, be noticed that several of Andrew Knight's varieties, which have endured longer than most kinds, were mi cd towards tho close of tbe last century by artificial crosses; some of them, I believe, were still, in 1860, vigorous; but now, in 1865, a writer, speaking 87 of Knight's four kinds of manows, says, they have acC)Uil'ed a famous history, but their glory has depart d. With rcsp<;ct to Beans (FctlJa vulgar-is), I will say but little. Dr. Alcfold has given 88 short diagnostic characters of forty varieties. Every one who bas seen a collection mnst have been struck with tho great diffcrcnco in shape, thicknesR, proportional length and breadth, colour, and size which beans present. What a contrast between a WinclRor and Horse-bean! As in the case of the pc::t, om existing v::triotics wore preceded during tho Bronze ::tgc in Switzerland by a peculiar and now extinct variety producing very small bean ·.89 Potato (.'-iolnnum tuberosum).-Thoro is little doubt about tho parentage of this plant; for tho cultivated varieties differ extremely little in general appearance from the wild species, which can be recognised in its native land at tho first glance.90 'l'ho varieties cultivated in Britain arc numerous; thus J-'aw ·on 91 gives a description of 175 kiuds. I planted eighteen kinds in adjoining rows; their stems anJ leaves differed but little, and in sevoml c::tses there was as grc::tt an amount of diftorcncc between the individu::tls of tho same variety as between the dift'crent varieties. Tho flowers vary in size, and in colour between white and purple, but in no other respect, except that in one lcinJ the sepals were somewhat elongated. One strange variety has been described which always produces two sorts of flowers, the first double and sterile, the second single ::tnd fcrtilc. 92 1'hc fruit or berries also differ, but only in a .·light dogrec.ua 86 I have published full details of oxpcrimcnls on t.llis subject in t.he 'Gardonor's Chronicle,' I 857, Oct 25th. 87 'Gunlcncr's Ol!roniclc,' 1865, p. i!87. B8 'Bonplandia,' x., 1 62, s. 34.8. 89 0. Uccr, 'Die l'Ilanzen ucr Pfahlbautcn,' 18GG, s. 22. 90 Darwin, 'Journal of Ucscarclws,' 18·15, p. 2155. 91 Synopsis of the v "'Ctnblc prodncl~ of Scotland, <]noted in Wilson's' British Farmi11g,' p. 317. 92 Sir G. Muckcnzic, in 'Gardener's Chronicle,' 1845, p. 700. 93 'I'utsche uncl V crluch V ersuch eiucr Monographic dcr Kartofl'eln,' 1810, s. D, 15. See also Dr. Anderson's ' Recreations in Agricult urc,' vol. iv. p. 325. CIIAP. IX. POTATOES. 331 Tho tubers, on tbo other h::tnd, present a wonderful amount of diversity. This fact accords with the principle that the valuable and selec~d p~rts of ::tll cultivated production.'> present tho greatest amount of mocl1ficatiOn. They cli11'cr much in size and shape, being globular, oval, flatten~d, kidney-like, or cylindrical. One variety from Peru is doscribed 94 as bcmg quito straight, ::tncl at least six inches in length, though no thicker than a m::tn's fin"'Cl'. Tho oyes or buds differ in form, position, and colour. The manner i~ which the tubers arc arranged on the so-called roots is different; thus in tho rJndcen-lcarto(fcln they form a pyramid with tho apex downwards, and in another variety they bury themselves deep in the ground. 'rlte roots thorns 1 vcs run either ncar tho surface or deep in the ground. Tho tubers ::tlso differ in smoothness and colour, being externally white, reel, purple, or almost black, and internally white, yellow, or almost black. They differ in flavour and quality, being either waxy or mealy; in their period of m::ttmity, and in their capacity for long preservation. As with many other plants which have been long propagated by bulbs, tubers, cuttings, &c., by which means tho same individual is exposed durin"' a length of time to diversified conditions, seedling potntoes generally display innumerable slight differences. Several varieties, even when propagated by tubers, are far from constant, as will be seen in t~o chapter on Bud-variation. Dr. Anderson 96 procured seed from an Ir·1sh purple potato, which grew far from any other kind, so that it could not at least in this generation have been crossed, yet the many seedlings varied in almost every possible respect, so that "scarcely two plants were exactly alike." Some of the plants which closely resembled each other above ground, produced extremely dissimilar tubers; and some tubers which externally could hardly bo distinguished, differed widely in quality when cooked. Even in this case of extreme variability, the parent-stock had some influence on the progeny, for tho grcator number of the seedlings resembled in some degree the parent Irish potato. Kidney potatoes must be ranked amongst the most highly cultivated and artificial races; yet their peculiarities can often bo strictly propagated by seed. A great authority, Mr. llivcrs,OG states that "seedlings from the ash-leaved kidney always bear a strong rescmbl::tnce to their parent. Seedlings from the flukc-lcidney are still more remarkable for their adherence to their parent-stock, for, on closely observing a great number during two seasons, I have not been able to observe tho least difference either in earliness, productiveness, or in the size or shape of then· tubers." !1·1 'Gnrcloncr's Chronicle,' 18G2, p. 1052. ur. • Bath Society Agricult. Po.pcrs,' vol. v. p. 127. And ' Recreations in Agriculture,' vol. v. p. 86. UG 'Gardener's Chronicle,' 18G3, p. 643. |