316 



LAWS OF VARIATION. 



Chap. XXIV. 



the bony protuberances which properly support the horns exfat *« 

 n . . '-'Alibi, tis merp 



rudiments. 



With cultivated plants it is far from rare to find the petals stain 

 and pistils represented by rudiments, like those observed in w *{ 

 species. So it is with the whole seed in many fruits ; thus near Astrakh 

 there is a grape with mere traces of seeds, " so small and lying so near tl 

 " stalk that they are not perceived in eating the grape. " 85 l u cer a • 6 

 varieties of the gourd, the tendrils, according to Naudin, are represents 1 

 Iby rudiments or by various monstrous growths. In the broccoli a 1 

 cauliflower the greater number of the flowers are incapable of expansion 

 and include rudimentary organs. In the Feather hyacinth {Muscari 



comosum) the upper and ' ' " 



mentary; under cultivation the tendency to abortion travels downwards 

 and outwards, and all the flowers become rudimentary ; but the abortive 

 stamens and pistils are not so small in the lower as in the upper flowers 

 In the Viburnum opulus, on the other hand, the outer flowers naturally 

 Iiave their organs of fructification in a rudimentary state, and the corolla 

 is of large size ; under cultivation, the change spreads to the centre, and 

 all the flowers become affected ; thus the well-known Snow-ball bush is 

 produced. In the Composite, the so-called doubling of the flowers con- 

 sists in the greater development of the corolla of the central florets, 

 generally accompanied with some degree of sterility ; and it has been 

 observed 86 that the progressive doubling invariably spreads from the cir- 

 cumference to the centre, 



include rudimentary organs, to those of the disc." I may add, as bearing 

 on this subject, that, with Asters, seeds taken from the florets of the 

 circumference have been found to yield the greatest number of double 

 flowers. 87 In these several cases we have a natural tendency in certain 

 parts to become rudimentary, and this under culture spreads either to, or 

 from, the axis of the plant. It deserves notice, as showing how the same 



jovern the changes which natural species and artificial varieties 



from 



laws 



in 



Compositse, a tendency in the seeds to the abortion of the pappus may be 

 traced extending from the circumference to the centre of the disc : thus, 

 according to A. cle Jussieu, 88 the abortion is only partial in Carthamus 

 creticus, but more extended in C. lanatus ; for in this species two or three 

 alone of the central seeds are furnished with a pappus, the surrounding 

 seeds being either quite naked or furnished with a few hairs ; and lastly, 

 in C.hnctoriw, even the central seeds are destitute of pappus, and the 

 abortion is complete. 



With animals and plants under domestication, when an organ dis- 

 appears, leaving only a rudiment, the loss has generally been sudden, as 

 with hornless and tailless breeds ; and such cases may be ranked as inhe- 

 rited monstrosities. But in some few cases the loss has been gradual, and 



voL i P p U 243. ' Tl ' aVelS '' EUg ' tranSki ' S? LeC0, l' ' De la Fecondation,' 1862, 



8(5 Mr. Beaton, in • Journal of Horti- 

 culture,' May 21, 1861, p. 133. 



p. 233. 



88 'Annales du Museum,' torn 

 p. 319. 



vi. 





r 



for 

 chi 





