72 THE SURVIVAL OF THE UNLIKE. * [ll. 



plasm with which it is indissolubly associated. I have 

 repeated this argument in order to introduce the subject 

 of "bud -variations," or those "sports" which now and 

 then appear upon certain limbs or parts of plants, and 

 which are nearly always readily propagated by cuttings. 

 These variations cannot be attributed to sex, in the 

 ordinary and legitimate application of the Weismannian 

 hypothesis. Whilst these "sports" are well known to 

 horticulturists, they are generally eonsidei'ed to be rare, 

 but nothing can be farther from the truth. As a matter 

 of fact, every branch of a tree is different from every 

 other branch, and when the difference is sufficient to 

 attract attention, or to have commercial value, it is prop- 

 agated and called a "sport." This leads me to recall 

 the ol^ discussion of the phytomer, or the hypothesis 

 that every node and internode of a tree — and, we might 

 add, the roots — is in reality a distinct individual , inas - 

 much as it possesses the power of leading an independent 

 existence when severed from the plant, and of repro- 

 ducing its kind. (See Essay III. for a fuller discussion 

 of this question.) However this may be as a matter of 

 speculation, it is certainly true as regards the phenom- 

 enon, and shows conclusively that if the germ -plasm 

 exists at all, it exists throughout the entire structure of 

 the plant. 



This conclusion — that the germ - plasm resides through - 

 out the soma — is also unavoidable from another consid- 

 eration : the fact that plants are asexual organisms at all 

 times previous to flowering, and that the germ -plasm 

 must be preserved, in the meantime, along with the 

 soma-plasm. In his essay upon the "Continuity of the 

 Germ -Plasm," Weismann cites the observation of Sachs 

 that ' ' in the true mosses almost any cell of the roots, 



