BOTANICAL SUBJECTS. 99 



of combined sexes in the more complex life kept that feature 

 extinguished in dioecious races.* 



We must not, however, suppose that the power of re-appearance 

 of a sex, where it was atrophied, became totally annihiliated, for 

 teratology shows us that not only can male organs replace female 

 organs, but the vegetative can replace the reproductive organs, 

 and vice versa. 



The ordinary axillary bud appears to contain the germs of 

 both sexes, for after going through the combined state in a 

 dormant condition, as leaves or vegetative cell-structures, they are 

 separated at the end of the branch as polliniferous and ovuliferous 

 leaves. In ferns, they are called barren and fertile fronds. 



"With the light of evolutionary ideas, strengthened by Weis- 

 mann's idea of continuity of germ-plasm, I do not see any good 

 reason why we should any longer hesitate to consider ferns, for 

 instance, as direct descendants of seaweeds. The latter might 

 indeed be called sea-ferns. 



There is abundant evidence to show that they are closely allied. 

 The ferns gradually emerged from a water life, becoming adapted 

 to an air life. 



There is sufficient evidence to show that not only ferns, but 

 also phcenogams, owe their forms to derivation from seaweeds. 



From all we know of the evolution of our earth, we are 

 justified in supposing that vegetable life commenced in water, and 

 that all subsequent developments of plant forms had their origin 

 in these primitive water forms, many of which, as I said, may still 

 be in existence now under the general name of seaweeds. 



We do not know why primitive plants have taken the forms 

 they have, rather than others, but some faint notion of how certain 

 low forms of vegetation may have come about may perhaps be 

 obtained by the study of mineral forms of crystallisation. 



The molecules of crystals appear to arrange themselves by the 

 force of polarity. We see some kinds arranging themselves in 

 what are called dendritic or tree-like forms, others are like moss ; 

 some are pinnate, others lobed, &c. It would appear as if 

 magnetic influence were acting on the crystals as they formed, 

 forcing the molecules to take up places in a way somewhat similar 



* Probably most dioecious plants are subject to polygamy, that is 

 reversion to hermaphrodite flowers. 



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