BOTANICAL SUBJECTS. 245 



The other point that remains to be worked out is : What can 

 have been the genesis of the axillary bud ? In other words, How 

 did it come there ? 



In the cryptogamic water plants, from which all land plants 

 must have evolved, we do not meet Avith any such organ as 

 the axillary bud of phsenogams. It cannot be that the bud is 

 better protected in the leaf axilla, for it is at the coldest season 

 that the leaf falls off, and leaves the dormant bud unprotected and 

 exposed to cold. The axillary bud is evidently intimately 

 associated with the leaf in origin, but, at the same time, it does 

 not wither and fall off with it. 



To search for the genesis of this axillary bud, then, we must 

 go back to a class of plants in which buds, as we mean them in 

 flowering plants, do not exist at all. This would seem Hke a 

 paradox ; it is not so, however. 



In seaweeds we do not find any axillary buds. In these lower 

 strata of vegetable life the leaves are branches or divisions of the 

 main stem, that is, they are all cladophyls or stem-leaves. Fig. 92 

 shows a portion of a leaf of Sargassum decurrens (FucaccEe).* 

 In this seaweed, and many others, we seem to have a hint of how 

 the axillary bud may have originated in land plants, which must 

 be considered as descendants of seaweeds. Here we have the 

 leaf, the flowering branch, the bract, and' the flower-bud of 

 phsenogams perfectly sketched out. From the leaf petiole, close 

 to what we would call the axilla, a raceme is given off with 

 alternate bracts. Again, from the petiole of each bract, near its 

 axilla, a smaller raceme of receptacles is given off, the lower 

 sub-division of which is modified into a vesicle or float. 



An evolutionist cannot desire a more perfect specimen in 

 seaweeds of the ancestral form of similar combinations in phasno- 

 gams. He has only to purge his mind of the old notions which 

 adhere to mere distinctions of words, in order to see the jjlain 

 relationship. In ferns, which may be considered as seaweeds, 

 emerged from water into air, the buds are also on the leaf-stalk, 

 as shown in Figs. 99 to 101. 



Now let the evolutionist consider how easy it would have been 

 for the petiolar raceme of this Sargassum to become wholly 

 axillary by the mere and trifling shortening of the petiole. The 



* PI. 145, " Harvey's Phyc. Austr." 



