EVIDENCE FURNISHED BY SCIENCE OF LIKENESSES. 131 



are simply grounds for the exhibition of wonderment and vain 

 surprise. 



Amongst the most important of the generalisations which Goethe 

 deduced from his study of the variations of plant structure and life, 

 was that which held that "the leaf is the type of the whole plant." 

 Not merely can it be shown that every appendage of the stem is a 

 leaf of one kind or another, but it may also be proved that the 

 plant itself arises from a seed which is in its essential nature merely 

 a peculiarly modified bud. Strange indeed is it to think that 

 between the gorgeous beauty of the blossom, or the complex nature 

 of the flower and its parts, and the simple leaf, there should exist such 

 close and intimate connection. But the likenesses or homologies 

 which underlie the varied forms of plants may be readily illustrated 

 by a brief reference to familiar facts of flower structure. Flower 

 buds spring from the protective base of leaves called bracts. Now, 

 these leaves exhibit every transition and gradation, from the ordinary 

 leaf of the plant to the more characteristic leaf we see protecting the 

 flower bud. Next in order, the botanist asks us to note that bracts 

 themselves may insensibly pass by easy ways and gradual stages to cor- 

 respond with the outer parts of the flower. There are four parts in a 



FIG. 56. WALLFLOWER. 



perfect flower (Fig. 56), arranged as circles or whorls of leaves placed in 

 an alternating fashion as to the individual leaves, one whorl within the 

 other. Beginning at the outside of the flower, we find the calyx (ca\ 

 composed, as a rule, of green leaves called sepals. Next comes the 

 brightly coloured part without which, in popular acceptation, a 

 " flower " would not merit the name the corolla (co), composed of 

 leaves called petals, which alternate with the sepals. These two 

 outer whorls are the floral envelopes. Within the corolla, we find the 

 stamens (st\ each consisting of a stalk and a head, in which latter is 

 developed the yellow dust called pollen, by which the " ovules " 

 are fertilised and converted into the fertile " seeds." Last of all, 

 and in the centre of the flower, the pistil (p) is to be noted. This 



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