WIND- AND SELF-POLLINATION 277 



away from the flower, is the production of nectaries 

 for their benefit on other parts of the plant. Or, again, 

 the stems, leaves, and the stalks of the flowers may 

 be armed with stiff" hairs, prickles, or thorns, which 

 prevent soft-skinned creeping animals, or very small 

 insects from climbing up to the flowers. Hairs 

 frequently occur on the calyx and on the petals, 

 which serve the same function, especially where the 

 flower droops, the bell of the corolla pointing directly 

 downwards to the soil. Examples of these types 

 of protection occur in the Bearded Campanula 

 (p. 89), the Tufted Campanula (p. 91), and the 

 Linnsea (p. 250), 



In other plants, the flower-stalks are rendered 

 slippery by a coating of wax, or the very smooth, 

 polished surface of the petals affords no hold for the 

 insect climber, or the secretion of some sticky material 

 by glandular hairs, on the stems or leaf-stalks, or 

 calyces, serves the same function. In other cases 

 different contrivances are met with, all fashioned to 

 the same end, but the above will perhaps suffice as 

 some indication of the commoner types of protection 

 met with in the Alps. 



Wind-pollination and Self-pollination. 

 Although, as we have seen, insect pollination is the 

 rule among Alpine plants, there are many exceptions 

 which are either wind-pollinated or self-fertilised. The 

 Coniferous trees and shrubs, for instance, are all wind- 

 pollinated. The same is true of the Green Alder, the 



