LIFE HISTORIES OF FAMILIAR PLANTS 



for insuring insect-fertilisation that the shghtest 

 acquaintance with their wondrous details is 

 sufficient to reveal what is almost the equivalent of 

 human design. Darwin, in referring to the flowers 

 of one of the species belonging to this same genus, 

 says : '^ As in no other plant, or indeed in hardly 

 any animal, can adaptations of one part to another, 

 and of the whole to other organisms widely re- 

 mote in the scale of nature, be named more perfect 

 than those presented by this orchis." 



The science of homology has shown that the 

 complex organisation of floral structure found in an 

 orchid is but a modification of some more simple 

 type of flower, such as a lily. A lily consists of 

 five alternating whorls of floral organs, composed 

 of three petal-like sepals, three petals, six stamens 

 in two whorls of three each, and, in the centre, a 

 pistil, or ovary, of three cells, or divisions ; how- 

 ever, if the general reader should endeavour to 

 trace these parts in an orchid flower his task would 

 now be a difficult one, for instead of the flower 

 being composed of fifteen parts, as in the lily, only 

 seven now remain. Three sepals and two petals 

 still exist as such ; the stamens have disappeared 

 entirely excepting the pollen-producing part of one 

 of them. The lost stamens are combined with the 

 pistil, or ovary, and with the remaining petal, to 

 form the structures known as the column and the 

 labellum respectively. 



Such modifications of the original parts of a 

 flower are, of course, not unusual ; a famihar 

 instance of such changes is that of the doubling ot 



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