BOTANICAL SUBJECTS. 69 



myriads of modifications we see in the whole of the animal and 

 vegetable worlds ! 



We find, too, that certain parts of organisms have on them 

 the stamp of persistent heredity, while other parts have varied 

 Avithout end. Take, for instance, the seven cervical vertebrae, 

 which run through the whole of the mammal series with but 

 trifling exceptions, while other parts have varied immensely. 



The column of a large section of orchids, combining the male 

 and female apparatus, has persisted hand in hand with innumerable 

 variations in other parts. The leaf and flower of the genus citrus 

 have changed little, excepting in [size, while the fruit has varied 

 very much. So of many other plants. The leaf of Phoenogams, 

 although it has undergone modification without end, has, never- 

 theless, persisted in an extraordinary manner, as far as its position 

 on the so-called stem is concerned. Galton calls the persistent 

 cause, " family likeness,^' and its opposite, *' individual variation." 

 He exemplifies these two factors by two miniature gardens full of 

 plants, giving rise to other miniature gardens by the scattering of 

 seeds from the first two. It would be next to impossible to have 

 the infant gardens exactly like the parent gardens, for the different 

 proportions of seeds would give rise to variation in the general 

 feature, although each infant^garden might comprise all the species 

 of the parent gardens. 



This, however, does not seem very different from Darwin's 

 Pangenesis, if we replace i^lants by germs. Indeed, the largeness 

 or smallness of the elements makes little difference, when the whole 

 process is an imaginary one. 



Now, in addition to all these factors of modification, with their 

 restraining heredity, there are two others which, in my opinion, 

 have largely influenced the production of the vegetable forms we 

 see. These factors ^tq fusion and^ssion. 



Fusion. 



The modifications produced by fusion must have been vast 

 although perhaps not sufficiently recognized. Passing over the 

 innumerable cohesions of carpels, stamens, petals, sepals, leaves, 

 &c., we find that two separate ovaries may fuse into one, forming 

 a larger ovary. This, we find, is not an uncommon occurrence;;in 

 the citrus genus, where two ovaries amalgamate and are eaclosed 



