G8 MORPHOLOGICAL DEVELOPMENT. 



principles of embryology, that in its rudimentary stages, the 

 phaanogainic shoot will have its foliar parts more clearly 

 marked out than its axial parts. This we see in every bud. 

 Every bud consists of the rudiments of leaves packed to- 

 gether without any appreciable internodal spaces; and the 

 internodal spaces begin to increase with rapidity, only when 

 the foliar organs have been considerably developed. More- 

 over, where nutrition falls short, and arrest of development 

 takes place that is, where a flower is formed the inter- 

 nodes remain undeveloped: the unfolding ceases before 

 the later-acquired characters of the phaBnogamic shoot 

 are assumed. Lastly, as the hypothesis leads us to expect, 

 axillary buds make their appearances later than the foliar 

 organs which they accompany; and where, as at the ends of 

 shoots, these foliar organs show failure of chlorophyll, the 

 axillary buds are not produced at all. That these are in- 

 ferable traits of structure, will be manifest on inspecting 

 Figs. 106 110; and on observing, first, that the doubly- 

 proliferous tendency of which the axillary bud is a result, 

 implies abundant nutrition; and on observing, next, that the 

 original place of secondary prolification, is such that the foliar 

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

 the bud 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 phsno- 

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



