236 



RECEPTION OF FLOWER-SEEKIXG 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 which prevail 

 for the exclusion of ants are so elaborate that one w^ould think that the honey of 

 Cuphea micropetala was 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 ^'2'*). These 

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



. 261.— sticky glands as a protection to Flowers. 



• Flower of Linncea borealis. 2 Calyx, inferior ovary and bracteoles of Linncea (considerably enlarged). ' Three ligulate 

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

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

 laria ; stalked glands shown 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. « Flower of Circcea alpiiia 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 flow^er, 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 flowers of Cuphea 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, S&npervivum montanum), and several Steppe-plants (Cleo7)ie 



