236 



RECEPTION OF FLOWER-SEEKING ANIMALS AT THE FLOWER. 



one of these canals. The admission of little ants to these flowers, insects 

 useless for purposes of pollination, and likely to block up the honey-orifices for 

 authorized visitors, would be disadvantageous. The arrangements w^hich prevail 

 for the exclusion of ants are so elaborate that one would think that the honey of 

 Cuphea micropetala w&s for them quite irresistible. The mouth of the flower is 

 rendered quite inaccessible to ants and other minute creeping insects by a fringe 

 of tufts, each bearing a number of divergent sticky bristles (262^'-'^). These 

 bristles form in the aggregate a chevaux-de-frise, guarding the mouth of the 



Fig. 261. — Sticky glands as a protection to Flowers. 



1 Flower of Linnoea borealis. 2 Calyx, inferior ovary and bracteoles of JAnnaea (considerably enlarged), s Three ligulate 

 florets from the capitulum of Crepis paladosa showing the glandular scales of the involucre immediately below them. 

 * Flower of Plumbago europcea ; the ribs of the calyx are provided with stalked sticky glands. 5 Flower of Ribes Grossu- 

 laria ; stalked glands sliown on the inferior ovary. •> Flower of Epimedium alpinum; the pedicel is glandular. " Section of 

 flower of Saxifraga controversa with sticky glands on pedicel, ovary, and calyx. 8 Flower of Circoea alpina with inferior 

 ovary covered with glands. * natural size ; all the other figures magnified. 



calyx-tube, through which these small visitors cannot penetrate. Flying insects, 

 however, which can reach the honey hovering at the mouth of the flower, and 

 such as can use the projecting stamens or stigma as support are not impeded 

 by the bristles, and are, so to speak, welcomed by the flow^ers of CupJiea micro- 

 petala. 



In addition to these plants, provided with adhesive glands about the flower 

 and its accessory structures, others exist in which the whole of the foliage is 

 sticky. As examples may be mentioned various Primulas (Primula glutinosa, 

 viscosa, villosa), Saxifrages (Saxifraga controversa and tridactylites), Crassulaceae 

 (Sedum villosum, Sempervivum nnontanum), and several Steppe-plants (Oleome 



