PROTECTION AGAINST UNBIDDEN GUESTS. 



237 



omithopodioides, Bouchea coluteoides, &c.). That their stickiness saves the 

 flowers of these plants from many undesirable visitors there can be no doubt. 

 Often enough the dead bodies of small creatures that have ventured upon them 

 may be seen adhering to the foliage. In some of them the plant actually 

 supplements its normal nutrition by a diet of these insects' bodies, and the 

 glandular hairs would appear to subserve the same functions as the similar 

 structures in Drosophylhmi lusitanicum, and the various species of Sundew and 

 Butterwort already described (c/. vol. i. pp. 153-156). 



This is the place to mention the waxy coatings of flowering axes and pedicels, 

 which, in a number of plants, guard the flowers from the approach of small creeping 



Fig. 265.— Sticky Bristles at the eJge of the Calyx as a protection to Flowers. 



I Flower of Ciiphea micropetala. - Longitudinal section of the same flower. 3 Transverse section of the same flower at the 

 height of the insertion of the style upon the ovary. ' Small portion of the calyx-limb showing the sticky bristles in little 

 tufts. 1, 2, 8 X 2 ; 4 X 8. 



insects — though, of course, in many cases they serve another function. The bloom 

 on the catkin-bearing twigs of the Violet Willow {Salix daphnoides) and Caspian 

 Willow {Salix pruinosa) undoubtedly plays this part. For these Willows, which 

 are dioecious and largely dependent upon bees for the transfer of their pollen, it is 

 of importance that the honey should be reserved for useful visitors and not need- 

 lessly wasted. Ants and the like, climbing up to the catkins and attempting to 

 traverse the wax-covered twigs, slip and lose their footing, and tumble down to the 

 ground again. 



It is not improbable, though no observations are to hand, that the stems and 

 branches of Melianthus, Dentaria, Sanguinaria, Fritillaria, &c., by their slippery 

 coating of wax provide a similar protection to the flowers which are rich in honey 

 in each case. 



It is especially hard chitinous insects, such as ants, whose progress is arrested 

 by sticky or waxy surfaces in the neighbourhood of the flower. Against snails and 



