Chap. X. FLOWEES. 393 



gave tip the attempt as too difficult for any one except a professed 

 botanist. Most of the varieties present such inconstant characters, 

 that when grown in poor soil, or when flowering out of their proper 

 season, they produced differently coloured and much smaller 

 flowers. Cultivators speak of this or that kind as being remark- 

 ably constant or true; but by this they do not mean, as in other 

 cases, that the kind transmits its character by seed, but that the 

 individual plant does not change much under culture. The 

 principle of inheritance, however, does hold good to a certain extent 

 even with the fleeting varieties of the Heartsease, for to gain good 

 sorts it is indispensable to sow the seed of good sorts. Neverthe- 

 less, in almost every large seed-bed a few almost wild seedlings 

 reappear through reversion. On comparing the choicest varieties 

 with the nearest allied wild forms, besides the difference in the 

 size, outline, and colour of the flowers, the leaves sometimes 

 differ in shape, as does the calyx occasionally in the length and 

 breadth of the sepals. The differences in the form of the nectary 

 more especially deserve notice; because characters derived from 

 this organ have been much used in the discrimination of most of 

 the species of Viola. In a large number of flowers compared in 

 1842 I found that in the greater number the nectary was straight ; 

 in others the extremity was a little turned upwards, or downwards, 

 or inwards, so as to be completely hooked ; in others, instead of 

 being hooked, it was first turned rectangularly downwards, and 

 then backwards and upwards ; in others, the extremity w^as con- 

 siderably enlarged ; and lastly, in some the basal part was depressed, 

 becoming, as usual, laterally compressed towards the extremity, 

 In a large number of flowers, on the other hand, examined by me 

 in 1856 from a nursery-garden in a different part of England, the 

 nectary hardly varied at all. Now M. Gay says that in certain 

 districts, especally in Auvergne, the nectary of the wild V. grandi- 

 flora varies in the manner just described. Must we conclude from 

 this that the cultivated varieties first mentioned were all descended 

 from V. grandiflora, and that the second lot, though having the 

 same general appearance, were descended from V. tricolor, of which 

 the nectary, according to M. Gay, is subject to little variation ? Or 

 is it not more probable that both these wild forms would be found 

 under other conditions to vary in the same manner and degree, 

 thus showing that they ought not to be ranked as specifically 

 distinct ? 



The Dahlia has been referred to by almost every author who has 

 written on the variation of plants, because it is believed that all the 

 varieties are descended from a single species, and because all have 

 arisen since 1802 in France, and since 180-1 in England. 188 Mr. 

 Sabine remarks that "it seems as if some period of cultivation had 

 been required before the fixed qualities of the native plant gave 



188 Salisbury, in ' Transact. Hort. semi-double variety was produced in 

 Soc.,' vol. i. 1812, pp. 84, 92. A Madiid in 1790. 



18 



