550 Summary F/Vto of the Progress of Gardenijig, 



can, by any process whatever, be made hardier in any climate, than 

 when first introduced into that climate, except by altering its 

 nature ; and this cannot be done by any process but one, and 

 that a process which renders the plant no longer the same spe- 

 cies, viz. cross breeding. 



The effect of the preceding winter on hybrid plants has led 

 to some interesting results respecting cross fecundation. It is 

 known to scient'.fic gardeners, that, in the case of hybrids gene- 

 rally, the progeny takes the constitution of the female parent, 

 while its characteristic features are those of the male. Hence, 

 it might have been foreseen, that a cross between i?6sa seraper- 

 florens and the Ayrshire rose, the latter being the female parent, 

 would produce a much hardier progeny, than if the crossing had 

 been reversed. It might also have been anticipated, that a cross 

 between the tree rhododendrons of Nepal and the i^hododen- 

 dron ponticum of the temperate parts of Asia, the latter species 

 being the female parent, would produce a much more tender 

 progeny, than a cross between the Asiatic tree rhododendrons 

 and those of North America, the latter being the female parent. 

 Hence, we are able to account for the apparently anomalous 

 circumstance of some of the Bengal hybrid roses having been 

 destroyed altogether by last winter's frost, while others have 

 been only partially injured ; and hence, also, we discover the 

 reason why the progeny of ^Rhododendron catawbiense, i^hod. 

 maximum, R. caucasicum, &c., fecundated by J?hododendron 

 arboreum, have stood the last winter, scarcely, if at all, injured ; 

 while the progeny of R. ponticum, fecundated by R. arboreum, 

 has invariably been killed down to the ground, or totally de- 

 stroyed. While the loss of some hybrid arbutuses is to be 

 accounted for on this principle, the mode of producing, by cross 

 fecundation, a number of others which shall be nearly as hardy 

 as the common species, is clearly pointed out. In short, the 

 confirmation of the general principle, that, in cross fecundation, 

 the constitution of the female parent prevails in the progeny, is, 

 we think, the most important gardening feature that has transpired 

 during the past year. 



It has long been known, that, among plants raised from seed, 

 whether the parent has been cross fecundated, or otherwise, there 

 is frequently considerable constitutional difference in the progeny; 

 some being hardier than others, and some being earlier or later 

 than the average of the species, of coming into leaf or flower. 

 These differences in seedlings may be seen on an extensive scale, 

 in every hawthorn hedge and oak wood ; and, in a more limited 

 way, they are exhibited in seedlings of different sorts of ever- 

 greens, such as the arbutus, Quercus /'lex, Portugal laurel, 

 MagnohV/ grandiflora, &c. The causes of this difference never 

 have, and, probably, never will be, discovered ; but, nevertheless. 



