THE MIKING AND UNMAKING OF FLOWERS. 



125 



honey, and while doing so the pollination is secured by means of the 

 insect itself, which thus unwittingly aids the plant. 



Such is the line of inductive evidence, leading to the conclusion that 

 all the adaptations to insect agency have resulted from the power of the 

 living protoplasm within the plant to respond to the irritations, and to 

 build up structures in correspondence with the requirements both of the 

 insects on the one hand, and of the plant itself on the other. 



Before concluding this part, I will give one more illustration, and 

 quote what I have said about it elsewhere.* 



The accompanying figures of the flow^ers of Duvernoia (fig. 55) show 

 how^ they are strictly in adaptation to the bee visiting them. Looking at 

 a alone (supposing we knew nothing of insect visitors), one might ask, 

 For what use is this great irregularity ? Why and how^ has it come into 

 existence ? And no answer is forthcoming. Now, turning to h, we see 

 one use at least. The weight of the bee must be very great ; and the 

 curious shape of the lip, with its lateral ridges, is evidently not only an 

 excellent landing-place, but is so constructed as to bear that weight. 

 Moreover, the two walls slope off, and are gripped by the legs and pressed 

 by the wings of the bee, so that it evidently can secure an excellent 

 purchase, and can thus rifle the flower of its treasures at its ease. 



It is almost always the anterior petal which furnishes the landing-place ; 

 if, however, the pedicel or inferior ovary has been too weak to support the 

 insect, then it has sometimes become twisted to supply additional strength. 

 The consequence is, that the posterior petal becomes anteri-or in position, 

 and is now the larger one, since it supplies the landing-place for insects, 

 as in orchids. This fact supplies an additional argument to the theory 

 that such irregular flowers are the result of insect agency. 



Part II. — The Unmaking of Flowees. 



Evolution is always accompanied by devolution or degradation, not to 

 add stagnation. This is a compensatory process ; not that it implies 

 anything derogatory, but it signifies that an organ which had its use 

 under previous conditions is no longer required under another set of 

 circumstances ; so that while new structures arise to fit the animal or 

 plant for new conditions of life, so the older ones tend to and often totally 

 disappear, or they remain as rudimentary structures. Hence animals 

 and plants abound vdih these so-called " rudimentary organs." 



In flowers we find that sometimes one part of a whorl, sometimes 

 another part, vanishes ; or again, whole whorls may disappear altogether, 

 so that a flower may become reduced to three, two, or one whorl only. 



A few illustrations will show this. Let us begin with the calyx. 

 When flowers are much crowded, this organ tends to be, and often is, 

 quite arrested. In Rhododendrons it remains as an almost invisible five- 

 toothed rim at the base of the corolla- tube. In Woodruft* (fig. 56), 

 Galiums, and in most members of the l^mbelliferous family there is 

 little or no trace of it. In all these the corolla, stamens and pistil are 

 present. 



* Origin of Floral Structures, p. 106. 



