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Show 408 CONCLUSION AND SUMMARY CIIAP. XI. t . 1 . ·e · Hopkirk 140 ently coloured :flowers, are compara 1ve Y ra1. · . bas seen this with Convolvulus trw. o l or; and 1' t I·S not ra. re with the Balsam and annual Delphinium. According ~0 Sir H. c1 1 01~- buro-k plants from the warmer t cm. pm .a t e r egwns ' when. cu tl-vatcb d ' under the hot ch• mate of St· D oml·l 1o-o are emmcntly b ' li~ble to lmd-variation; but change of climate is by no means ,a necessary con tm' gen t ' 'a s we sec with tho .g ooseberry, cuar· ra·n t, an d some o· t hc rs. .n1: ]a' tlts living un•d er the1• r natmal dc on 11 t10. ns1 are very rare1 y su bJ. CC t t o bucl-variatwn : vanegated an co om ec leaves have however, been occasionally observed; and I have . . ' t f the variation of buds on an ash-tree ; but o·1ven an ms ance o it is doubtful whether any tree planted in ornamental gr_o~nc1 s can be cons1· a ered as 1I.V I·n cbr under strictly• natural conchtwns. Ga.. rtner b as seen w1 n · te a nd darl··' -red flowers produced from the same roo t of . the \VI'ld Acl~illea mille:+J' 'olium; and P• ro• f. Oaspa• ry b as soon ,1r w· l a zu t ea , 1·n a com1)letely wild conditwn, bearmg flowers of different colours and sizes.I41 . . . As wild I lauts are so rarely liable to bud-van.ab?n, whilst highly cultivated plants long propagated by art1~c~al means have yielded by this form of reproduction many vanetws, we are led throuo-h a. series such as the following,-namely, all the eyes in the sa~e tuber of the potato varying in tho same ~anner,all the fruit on a purple plum-tree suddenly becommg ycll~w, -all the fruit on a double-flowered almond s~dde~ly becommg eaeh-like,-all the buds on grafted trees bemg m some very ;light degree affected by the stock on which they have b~en worked -all the flowers on a transplanted heartsease changmg for a ti~1e in colour, size, and shapc,-we are led th~ough such facts to look at every case of lmd-variati?n as the duect result of tho particular conditions of life to whiCh the pla.~t has been expose d . B u t if we turn to the other end. of the se1n es,· nambe ly, to such cases as that of a peach-tree which, after. laVIng een cultivated by tens of thousands during many yearsm many countries, and after having annually produced thousa~ds of buds, all of which have apparently been exposed to preCisely the. sa~e conditions yet at last suddenly produces a single bud with ~ts whole char' acter greatly transformed, we are d n·v en t o an op pos1te 140 'Floro. Anomala,' P· .~G4. .. . , · F •b 3 1865 s. 4. HI • Scllriftcn dcr Pl1ys.-Okoa. Gc;;cll. zu Kuutg::;bcrg, Band v1., c · • • CHAl'. XL OF THE CIIAPTER. 4.09 conclusion. In such cases as tho latter it would appear that the transformation stands in no direct relation to the conditions of life. We have seen that varieties produeed from seeds and from buds resemble each other so closely in general appearance, that they cannot possibly be distinguished. Just as certain species and groups of species, when propagated by seed, arc more variable than other species or genera, so it is in the case of certain bud-varieties. Thus the Queen of England Chrysanthemum has produced by this latter process no less than six, and Rollisson's Unique Pelargonium four distinct varieties; moss-roses have also produced several other moss-roses. The Rosaceoo have varied by buds more than any other group of plants; but this may be in large part dne to so many members having been long cultivated; but within this one group, the peach has often varied by buds, whilst the apple and pear, both grafted trees extensively cultivated, hnve afforded, as far as I can ascertain, extremely few instances of bud-variation. The law of analogous variation holds good with varieties produced by buds, as with those produced from seed: more than one kind of rose has sported into a moss-rose; more than one kind of camellia has assumed an hexagonal form ; and at least seven or eight varieties of the peach have produced nectarines. The laws of inheritance seem to be nearly the same with seminal and bud-varieties. vVo know how commonly reversion comes into play with both, and it may affect the whole, or only segments, of a leaf, flower, or fruit. When the tendency to reversion affects many buds on the same tree, it becomes covered with different kinds of leaves, flowers, or fi·uit; but there is reason to believe that such fluctnating varieties have generally arisen from seed. It is well known that, out of a number of seedling varieties, some transmit their character much more truly by seed than others; so with bud-varieties some retain their character by successive buds more truly than others; of which instances have been given with two kinds of variegated Euonymus and with certain kinds of tulips. Notwithstanding the sudden production of bud-varieties, the characters thus acquired are sometimes capable of transmission by seminal reproduction: Mr. Rivers has found that moss-roses generally VOL. I. 2 E |