298 THE EFFECTS OF CKOSSING CHAP. VIIL 



crossing flowers on the same plant.* In opposition to 

 this conclusion is the fact that a bud is in one sense 

 a distinct individual, and is capable of occasionally or 

 even not rarely assuming new external characters, as 

 well as new constitutional peculiarities. Plants raised 

 from buds which have thus varied may be propagated 

 for a great length of time by grafts, cuttings, &c., and 

 sometimes even by seminal generation.! There exist 

 also numerous species in which the flowers on the 

 same plant differ from one another, as in the sexual 

 organs of monoecious and polygamous plants, in the 

 structure of the circumferential flowers in many Com- 

 positae, Umbelliferee, &c., in the structure of the 

 central flower in some plants, in the two kinds of 

 flowers produced by cleistogamic species, and in 

 several other such cases. These instances clearly 

 prove that the flowers on the same plant have often 

 varied independently of one another in many im- 

 portant respects, such variations having been fixed, 



* It is, however, possible that ments have been made with re- 

 the stamens which differ in length spect to the stamens of Pelargo- 

 or construction in the same flower nium. With some of the Mela- 

 may produce pollen differing in stomacese, seedlings raised by me 

 nature, and in this manner a cross from flowers fertilised by pollen 

 might be made effective between from the shorter stamens, cer- 

 the several flowers on the same tainly differed in appearance from 

 plant. Mr. Macnab states (in a those raised from the longer sta- 

 communication to M. Verlot, ' La mens, with differently coloured 

 Production des Varietes,' 1865, anthers ; but here, again, there is 

 p. 42) that seedlings raised from some reason for believing that the 

 the shorter and longer stamens of shorter stamens are tending to- 

 rhododendron differ in character ; wards abortion. In the very dif- 

 but the shorter stamens appa- ferent case of trimorphic hetero- 

 rently are becoming rudimentary, styled plants, the two sets of sta- 

 and the seedlings are dwarfs, so mens in the same flower have 

 that the result may be simply due widely different fertilising powers, 

 to a want of fertilising power in f I have given numerous cases 

 the pollen, as in the case of the of such bud-variations in my ' Ya- 

 dwarfed plants of Mirabilis raised riation of Animals and Plants un- 

 by Naudin by the use of too few der Domestication,' chap. xi. 2ud 

 pollen-grains. Analogous state- edit. vol. i. p. 448. 



