BOTANICAL SUBJECTS. 25^ 



the stem and the leaf, as one and the same thing ^ " Bower regards 

 the whole leaf in vascular cryptogams, from apex to base, as an 

 axis (or stem), the phyllopodium, which may be branched or 

 nnbranched."* 



Looking at the whole question from ah evolutionary point of 

 view, there can remain no doubt that the axis or stem, and leaf, 

 (caulome and phyllome) are one and the same thing. Land 

 plants could not have evolved from any other than seaweeds. In 

 these we find, as in Gigartina lanceolota (Fig. 16) and Fucus 

 margiyiifer (Fig. 20) and others, that there is no differentiation of 

 stem and leaf, and that the margin of the cladophyl, or leaf-stem, is 

 often the budding surface. In Fucus marginifer, if a lobe were 

 separated, it would, like a seed, grow into a 'plant. When a 

 stiffening midrib was evolved, there was still no differentiation 

 of stem and leaf, as in Delesseria (Fig. 12). But the midrib also 

 assumed the office of budding surface. When the wings or blades 

 decayed, the midrib remained as the stem. Therefore, the marginal 

 bud of the leaf, the midrib bud, and the stem bud are all one and 

 the same thing. 



It follows that the ovule is a special leaf -bud, evolved through 

 natural selection, because it was a benefit to the species to vary. 

 This variation was brought about by the mingling of the contents 

 of the male bud (pollen) with that of the female bud (ovule). 

 This mingling became of such importance that elaborate appliances 

 were evolved by which insects were forced to take a very extensive 

 part in this process. 



No one now doubts that the carpel which bears the ovules is 

 any other than a form of leaf.f The elaborate paper of Warming 

 just noticed is a controversy about words. The difficulty of 

 recognizing that the bud and the ovule are one and the same 

 thing arises not from the things themselves, but from the different 

 names that were originally fixed on to them. It shows how 

 cautious new investigators should be in handing down unnecessary 

 terms to future generations. Often they only waste time and 

 mental energy. 



How it is possible to make the ovule anything but a bud is to 

 me inconceivable. If it aborts as a bud, it becomes a tooth or a 



* Goebel's " Outlines of Classif.," note to p. 214. 

 f Vide Carpels of Sterculia, Fig. 103. 



