290 SIGNIFICANT VESTIGES IN 



existing flowers." Their flat, symmetrical, open corollas prove 

 them to be but little specialisedj and they still bear the fifth 

 stamens which their more advanced cousins have discarded. 



Most of the members of the Bignonia family are tropical, and 

 those which are habitues of this soil have somewhat the air of 

 strayed exotics. The Bignonia carreolata festoons the trees which 

 fringe our southern rivers, hanging its great showy orange and 

 crimson flowers from the topmost boughs ; and more familiar 

 members of the family are the Catalpa tree and the Trumpet 

 Creeper of our gardens. The Bignonia and the Trumpet Creeper 

 have each four stamens, with a very evident rudiment of a fifth. 

 In the Catalpa the process of elimination has gone still further, 

 and the flower bears but two perfect stamens, and two or three 

 little white threads, which are reminiscences of the rest. All these 

 flowers which possess stamens growing small by degrees and beau- 

 tifully less are monopetalous and most of them are deep-throated. 

 In such flowers the pollen is thriftily preserved to meet the needs 

 of fertilisation. The stamens are, in most cases, partially pro- 

 tected from wind and rain, and the pollen is therefore less likely 

 to be blown or washed away. Moreover, the monopetalous flower 

 is comparatively safe from insect robbers. In a polypetalous 

 flower, which keeps open house, as it were, to all comers, a crawl- 

 ing insect can slip in between the petals, rob the nectaries, " eat 

 the pollen," says Grant Allen, " to his heart's content," and go out 

 the same way he came in, dusted with pollen which probably will 

 never be carried where it should go — to another flower of the 

 same species. The tubular blossom is more difficult to enter and 

 less likely to be robbed, and, in many cases, it bids for the atten- 

 tion of a select circle of visitors by keeping its nectar out of the 

 reach of the vulgar mob, and accessible only to larger-winged 

 insects. Polypetalous flowers, especially those with shallow cups, 

 must produce enough pollen to meet Nature's requirements after 

 many mischances have been endured, and must hence be liberally 

 supplied with stamens. But with the union of the petals fewer 

 stamens are needed to supply Nature's needs, and the more the 

 blossom is tubed, the more closely, as a rule, are its anthers brought 

 together, and the more accurately are they pressed against the 

 body of any visiting insects. 



