THE MORPHOLOGICAL COMPOSITION OF PLANTS. 65 



surface on which it occurs, must grow to some extent before 

 the hud appears. 



On thus looking at the matter — on contemplating afresh 

 the ideal type shown in Fig. 106, and noting how, by the 

 conditions of the case, the secondary prolifications must cease 

 before that primary prolification which produces the main 

 axis ; we are enabled to reconcile all the phenomena of axil- 

 lary gemmation. We see harmony among the several facts — 

 first, that the axillary bud becomes a lateral, leaf-bearing 

 axis if there is abundant material for growth ; second, that 

 its development is arrested, or it becomes a flower-bearing 

 axis, if the supply of sap is but moderate ; third, that it is 

 absent when the nutrition is failing. We are no longer 

 committed to the gratuitous assumption, that in the phseno- 

 gamic type, there must exist an axillary bud to each foliar 

 organ ; but we are led to conclude, a priori, that which we 

 find, a posteriori, that axillary buds are as normally absent 

 in flowers as they are normally present lower down the 

 axis. And then, to complete the argument, we are prepared 

 for the corollary that axillary prolification may naturally 

 arise even at the ends of axes, provided the failing nutrition 

 which causes the dwarfing of the foliar organs to form a 

 flower, be suddenly changed into such high nutrition as to 

 transform the components of the flower into appendages 

 that are green, if not otherwise leaf-like — a condition under 

 which only, this phenomenon is proved to occur. 



§ 195. One more question presents itself, when we con- 

 trast the early stages of development in the two classes of 

 Phsenogams ; and a further answer supplied by the hypothe- 

 sis, gives to the hypothesis a further probability. It is cha- 

 racteristic of an endogen, to have a single seed-leaf or coty- 

 ledon ; and it is characteristic of an exogen, to have at least 

 two cotyledons, if not more than two. That is to say, the 

 monocotyledonous mode of germination everywhere co- 

 exists with the endogenous mode of growth ; and along with 



