BOTANIC A L jjUBJECT.-?. 255 



ofteiier as u biaiiclilct ut" the pL4iuk', in its axilla, and adnatc to the. 

 stem. It is protected by separate bud-scales. It has no need of 

 special bud-scales which act as cotyledons,* l^ecause it is nursed 

 by the parent stem. The result is a branch not subject to 

 variation. Like the buds of polyps, it lives attached to its parent. 

 This, however, is not always the case, because in the lily the 

 axillary bud separates from the parent as the seed does. 



Prof. "Weismann (" On Heredity," p. 225) discusses the causes 

 of parthenogenesis. " The formation of i)olar bodies has been 

 repeatedly connected with the sexuality of germ cells." .... 

 Minot and Balfour maintain that the polar body is the male part 

 of the hermaphrodite egg-cell, and that an egg, which has lost its 

 male part, cannot develop into an embryo until it has received a 

 new male part in fertilization. On the other hand, an egg which 

 does not expel its male part may develop without fertilization.! 

 In a note, Prof. Weismann says that " the formation of a polar 

 body in parthenogenetic eggs has now been proved." 



All this may modify our conception of the cause of partheno- 

 genetic seeds, as distinguished from pollinated seeds, but it does 

 not touch the fact of their Ijeing both branches, and, therefore, 

 homologous with the axillary bud, or any other bud. 



Whether there be one or more polar bodies in the ovule is of 

 little imix)rtance. I take my stand upon the acceptance of the 

 leaf being a stem, and upon the fact that both the bud and the 

 ovule eventually develop into branches or stems. Therefore, the 

 ovTile on the margin of the carpophyl, as in Sterculia, is as much a 

 bud as the marginal bud of the Bryophyllum leaf, or as much a 

 bud as the axillary bud on the stem proper. 



The facts of parthenogenesis leads us to believe that we have 

 two kinds of carpellary buds, the ordinary or parthenogenetic bud, 

 and the fertilizable bud. The former would produce the parent 

 form, tale quale, as an axillary bud would do, while the latter 

 being fertilized would vary. 



If the parthenogenetic bud is so, owing to some modification 

 connected with polar bodies, as Weismann states, then it would 

 follow, prima facie, that the axillary or other ordinary bud has 

 some similar or paralkd modification by which it can develop into 



* Vide cotyledons in another place. 



I That is, it will produce a branch pure and simple, as the bud doefs. 



