114 THE FLOWER 



as iii possessing what answer to the veins or ribs of leaves, 

 fibrous elements coming out from the flower stem. 

 Occasionally stamens and pistils are found which have 

 failed to develop in their proper character. They then 

 take the shape of foliage leaves, more or less exactly. 

 The conclusion is inevitable, from all these considerations, 

 that the essential organs of the flower, as well as the floral 

 envelopes, are morphologically leaves. 1 



219. The carpels, in this conception, become leaves rolled inward, 

 bearing on the inrolled edges rows of ovules. When the pistil is 

 simple (of one carpel or leaf), a seam, the ventral suture, marks the 

 closing together of the ovuliferous leaf on the side toward the center 

 of the flower ; while a ridge up and down the opposite side of the pis- 

 til evidently stands for a midrib. 



220. Departures from a simple floral plan. If one were to examine 

 the first score of different flowers that he should meet on going into 

 the field, he would probably find among them few or none that display 

 the regularity, simplicity, and completeness spoken of in 217. The 

 fundamental plan that is, the order and mode of growth, num- 

 ber of parts, etc. would be found in many cases to be obscured 

 by a variety of adaptations to the special functions of the flower. 

 Some of the commonest modifications to be discovered are the 

 following : 



221. Absence of some of the organs. 2 Occasionally the gradual dis- 

 appearance of some of the organs may be directly noted, as in stamens 

 lacking the anther, or reduced to a mere ridge or rudiment ; or in the 

 reduction of one whorl of the perianth to an inconspicuous ring. In 

 many of the trees and shrubs the perianth will be found to consist of 

 only the calyx (e.g. in the Elm), or it may even be wanting (e.g. in the 

 Buttonwood). And two cases have already been mentioned (the Wil- 

 low and the Pine) where each flower contains but one kind of essen- 

 tial organ. 



222. Union of like parts, or coalescence, of which examples have 

 been given above. 



1 This is not to be construed to mean that what were once merely 

 foliage leaves have in the course of time been modified so as to become 

 carpels, stamens, etc. All that is to be inferred here is that both foliage 

 leaves and floral organs have a common morphological nature, as foliar 

 appendages of the stem. 



2 It is possible to suppose in some cases that the fewness of parts, or 

 the absence of certain organs, has come about, not by reduction from 

 more highly organized forms, but by inheritance from ancestry charac- 

 terized by simple flowers from the first. 



