EXPERIMENTS IN CROSSING. 489 



other : but, if one of the parents is quite hardy, and the other 

 not quite able to support our winters, the probability is, that 

 the offspring wiU support them, though it may suffer from 

 a very unusual depression of the thermometer, or excess of 

 moisture, which would not destroy its hardier parent." 



" In few characters is the influence of muling more striking than in 

 the size and colour of hlossoms. In many closely allied spebies, which 

 differ hut little in habit or foliage, the colour of the coroUa is of great 

 importance. In a wild state it is for the most part constant, and is 

 often indicative of distinct groups or species. In other groups, on the 

 contrary, it is extremely variable, and is notably different at different 

 periods of growth. Where, however, colour is the most constant and 

 distinctive, union is often practicable, and in general the consequence 

 of hybridisation is a complete derangement of the laws on which such 

 constancy of hue depends. Neither axe the hues resulting from the 

 union necessarily intermediate. Blue and yellow, for instance, do not 

 produce green, as is proved by Verbascum phoeniceum and phlomoides. 

 Gladiolus cardiuaU-blandus exhibits the less briUiaht hue of the male 

 parent rather than the splendour of the mother ; and in some cases the 

 tone of colour of one of the parents is exhibited under a more briUiant 

 tint, as in Mcotiana suaveolenti-gliitinosa. 



"Little has been done at present in the hybridising of cereals, but 

 Herbert believed that more useful varieties than at present exist of 

 Wheat, Oats, and Barley, might be produced by combining the fruit- 

 fulness of one variety with the hardiness of another, to both of which 

 might be added the thin sldn and, consequent superior weight of a third. 

 Knight's wrinMed Peas are a proof of what may be done by hybridising, 

 and it is probable that much might be effected in Beet, Cabbages, Car- 

 rots; Celery, &c,, by especial attention to this point. 



"Amongst woody plants also there are instances of peculiarly 

 luxuriant growth, such as Lycium barbato-afrum. Varieties therefore 

 might be produced, of much more rapid growth, which for some pur- 

 poses might have their value, though the quality of the timber would 

 probably suffer. 



" Another peculiarity of hybrids is their precocity, of which advan- 

 tage may be taken where early fruit is desirable, or where the summers 

 are not long enough to ripen the later fruit. 



" A very important quality of hybrids is also their power in very 

 many cases of enduring a greater degree of cold than the pure species 

 from which they are derived, and hence the acclimatisation of many 

 useful plants by means of hybrid forms or varieties may be effected. 

 The hybrids, for instance, of Nicotiana are far less susceptible of frost 

 than their pure parents, a circumstance of very great importance if the 

 cultivation of Tobacco were to be materially extended. 



