September 5, 1901] 



NA TURE 



447 



the Welwitschia, now in cultivation at Kew and else- 

 where, was, in garden parlance, a new plant. It was 

 new to Welwitsch when he discovered it in the deserts 

 of Mossamedes in South-West Africa, but nobody 

 looking at the uncouth "monster" would deem it 

 new. Rather would he think of it, as he has a clear right 

 to do in the case of the Ginkgo, as a survival from a pre- 

 historic past. Welwitschia has not, so far as we know, 

 been discovered in a fossil state, but if our Antarctic 

 " discoverers " should light upon its traces near the 

 South Pole, no one would be greatly surprised. 



In such cases as these, then, it is the introduction into 

 gardens as cultivated plants that constitutes the novelty. 

 And so it is with the hosts of species of orchids, palms, 

 ferns and other plants with which the zeal of botanists 

 or the enterprise of collectors enriches our gardens. 

 Many of these are absolutely new — new to science, that 

 is, as well as new in gardens. Others are novelties so 

 far as the garden is concerned, but have previously been 

 known to, and duly recorded by, the botanist. 



But there is still another category of " new garden 

 plants," and one of such vast interest to the student of 

 evolution that we , cannot but express our astonish- 

 ment that so fertile a field of research has hitherto 

 attracted so few labourers. We allude to new plants 

 actually created in gardens by the skill of the gardener. 

 The materials, no doubt, exist in nature, the gardener 

 does but rearrange them, as the milliner forms " ravish- 

 ing creations " by tasteful intermi.\ture of tulle and 

 ribbon. But the gardener does more than the milliner. 

 He not only effects kaleidoscopic changes of the same 

 materials, but he sets in operation previously pent-up 

 forces — forces which are made manifest in the phenomena 

 of variation, adaptation and progressive evolution. The 

 modern gardener, by means of incessant vigilance and 

 adjustment of the conditions of environment, so far as he 

 is able to do so, cultivates the plants committed to his 

 charge so as to obtain the most healthy foliage, the finest 

 flowers or the most luscious fruit according to his 

 particular requirements. But cultivation is not every- 

 thing. It improves the old, but it does not create the 

 new. Selection, again, by which the gardener profits 

 much, does not in all cases result in absolute novelty, 

 but only in enhanced quality, a lessened amount of 

 variability and a greater degree of fixity or constancy. 

 A seedsman's "stock" of broccoli, or whatever it may 

 be, is carefully " selected" by the choice and retention of 

 ■ what is required and by the rejection or elimination of 

 what is not desired. The " rogues," that is the plants 

 which do not come up to the high standard of perfection, 

 are ruthlessly destroyed. By these procedures, carried 

 on year by year, the stock at length becomes almost 

 absolutely pure, and, what is more, it is kept so because 

 the tendency to vary has become quiescent. Alter the 

 conditions, exercise less vigilance, variation will again set 

 in and the stock become correspondingly deteriorated. 

 Cultivation, selection and elimination tend to preserve 

 the old rather than to create the new. 



Novelty in garden plants, apart from the direct im- 

 portation of new species from foreign countries, is secured 

 in various ways, such as the conservation or selection 

 of variations which originate naturally. By repeated 

 selection and elimination the desired variation is, as we 

 have just said, finally "fixed." It becomes constant and 

 capable of reproduction by seed. Another method of 

 obtaining novelties is by the observation, retention and 

 propagation of bud-variations or sports. A third and 

 most efTectual means is secured by the practice of cross- 

 breeding. 



\'ariation in some degree is almost universal ; no two 

 leaves on the same branch are alike, the peas in a pod 

 really contradict the meaning of the proverbial adage, 

 for, instead of being strictly alike, they are more or less 

 different. But the discontinuous variation, the " sport " 



NO. 1662, VOL. 64] 



proper, as it is understood in gardens, is the representa- 

 tive |of a more pronounced degree of variation— one that 

 occurs suddenly, or at least its earlier manifestations are 

 so inconspicuous as to be overlooked. It appears simulta- 

 neously in widely separated areas. It is mysterious in 

 origin as it is striking in appearance. No doubt in many 

 cases this sporting is a reversion to some ancestral 

 condition, or is due to a separation of previously 

 amalgamated characteristics, but what brings about the 

 separation is a mystery. In any case, the gardener has 

 little or no control over the phenomena of sporting ; he 

 does but avail himself of what nature provides him 

 without any effort of his own. 



It is a very different thing with cross-breeding. The 

 larger number of "new garden- plants " at the present 

 day are due to intentional cross-pollination or fertilisation. 

 .AH degrees of this process occur from the union of male 

 and female elements from individuals that present the 

 least degree of distinctiveness up to the combination of 

 the sexual elements in plants so wide apart as to be, for 

 practical purposes at any rate, placed in distinct genera, 

 and in one recorded case in a distinct order. Bigeneric 

 hybrids have been recorded between Philesia and Lapa- 

 gL'i-ia ( = Philageria x Mast.), between Urccolina and 

 Eucharis { — \ixctoAax\i x Mast.), belween /i^oc/iea fa/- 

 ciitd and Crassula coccitica (= Kalorochea x Veitch), 

 IJbonia and Sericograpliis ( = Sericobonia x ), between 

 Monthft-tia and Tritoiiia, between numerous genera of 

 Gesneracea;, between Scilla and Cliionodoxa (' = Chion- 

 oscilla X ). Amongst orchids no fewer than 150 bigeneric 

 crosses are recorded (Hurst, in Journal of the Royal 

 Horticultural Society, 1900, vol. xxiv. p. 102). 



In 1849 Donckelaar, the younger, the curator of the 

 Botanic Garden at Ghent, raised a hybrid out of Gestiera 

 discolor by pollen of a Gloxinia. This was called Gesnera 

 Donckclaariaua by Lemaire in the Jardin Fleuriste 

 (1854), t. iv. p. 382. The good faith of the gardener was 

 needlessly and unjustly impugned, and the hybrid nature 

 of the plant was doubted by Decaisne, as was not un- 

 natural at that time. But now that, as we shall presently 

 see, the gardener has succeeded in actually producing 

 by art the same form that exists in nature, there is no 

 more occasion for scepticism. 



Decaisne suggested that Donckelaar's plant was no 

 hybrid, but a new species accidentally introduced with 

 other species of Gesneraceie. This view received confir- 

 mation some years later when Messrs. X'eitch received 

 from Colombia a plant which on flowering presented all 

 the characteristics of Gesnera Donckelaariana. This 

 plant was figured and described as a species by Sir 

 Joseph Hooker in the Botanical Magazine, t. 5070 (1858). 

 Several years afterwards (in 1894) Messrs. Veitch pro- 

 duced a hybrid between Gesnera pyra?nidalis crossed with 

 pollen of Gloxinia " Radiance." This received the name 

 of " Gloxinera x ," and is a sufficient proof that bigeneric 

 hybrids may occur in Gesneracea. The Gloxinera was 

 figured and described by Mr. J. Weathers in the 

 Gardeners' Chronicle (February 2, 1895), and formed the 

 subject of an interesting note from Count de Kerchove de 

 Denterghem in a subsequent number (February 9, 1895, 

 P- 175)- 



Many other bigeneric hybrids are recorded among the 

 GesneraceJB, but, until botanists have agreed as to the 

 limitations and nomenclature of genera in this order 

 (which they are far from having done at present), we 

 must suspend our judgment as to the precise status of 

 the numerous hybrids that are alleged to have been 

 raised. For an account of them up to the time of pub- 

 lication, the reader may be referred to Mr. Burbidge's 

 excellent work on "Cultivated Plants, their Propagation 

 and Improvement" (1877), and to Dr. Focke's "Die 

 Pflanzen Mischlinge" (18S1), p. ^26 etseg. 



A still further degree of hybridisation is recorded in 

 Maund's "Botanic Garden" (v. p. 468), where a cross 



