530 LAWS OF VARIATION. Chap. XXV. 



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main permanently blue and the ears would be incapable of per- 

 ceiving sound ; and we should thus understand this curious case. 

 As, however, the colour of the fur is determined long before 

 birth, and as the blueness of the eyes and the whiteness of the 

 fur are obviously connected, we must believe that some primary 

 cause acts at an early period. 



The instances of correlated variability hitherto given have 

 been chiefly drawn from the animal kingdom, and we will now 

 turn to plants. Leaves, sepals, petals, stamens, and pistils are 

 all homologous. In double flowers we see that the stamens and 

 pistils vary in the same maimer, and assume the form and colour 

 of the petals. In the double columbine (Aquilegia vulgaris), the 

 successive whorls of stamens are converted into cornucopias, 

 which are enclosed within each other and resemble the petals. 

 In hose-and-hose flowers the sepals mock the petals. In some 

 cases the flowers and leaves vary together in tint : in all the 

 varieties of the common pea, which have purple flowers, a 

 purple mark may be seen on the stipules. In other cases the 

 leaves and fruit and seeds vary together in colour, as in a 

 curious pale-leaved variety of the sycamore, which has recently 

 been described in France, 23 and as in the purple-leaved hazel, in 

 which the leaves, the husk of the nut, and the pellicle round 

 the kernel are all coloured purple. 24 Pomologists can predict 

 to a certain extent, from the size and appearance of the 

 leaves of their seedlings, the probable nature of the fruit ; for 

 as Van Mons remarks, 25 variations in the leaves are generally 

 accompanied by some modification in the flower, and con- 



sequently in the fruit. In the Serpent melon, which has a 

 narrow tortuous fruit above a yard in length, the stem of the 

 plant, the peduncle of the female flower, and the middle lobe 

 of the leaf, are all elongated in a remarkable manner. On the 

 other hand, several varieties of Cucurbita, which have dwarfed 

 stems, all produce, as Naudin remarks with surprise, leaves of 

 the same peculiar shape. Mr. G. Maw informs me that all the 



of the scarlet Pelargoniums which have contracted 





imperfect leaves have contracted flowers : the difference between 



23 < Gardener's Chron.,' 1864, p. 1202. 



24 Verlot gives several other instances, ' Des Variete's,' 1865, p. 72 



25 ' Arbres Fruitiers,' 1836, torn. ii. pp. 204, 226. 





