98 THE STORY OF THE PLANTS. 



only ; they crawl up one stem after another 

 indiscriminately, and steal the nectar which the 

 plant intends for its regular winged visitors. 

 Even if they do occasionally fertilise a flower, 

 it will probably be with pollen of another kind, 

 so that the result will be, not a perfect plant, but 

 a miserable hybrid, ill adapted for any condi- 

 tions. Hence plants usually possess advanced 

 devices for keeping off ants and other climbing 

 thieves from their precious honey. Hairs on 

 the stalk and calyx are enough to secure this 

 object in the meadow buttercup, which has a tall 

 stem, and therefore is not so easily climbed ; 

 for the hairs, small as they look to us, prove to 

 the ant a perfect forest of underwood. But in 

 the early bulbous buttercup, which has a shorter 

 stem, and the smell of whose honey is therefore 

 more alluring to the groundling ant, this device 

 is not alone sufficient ; so the calyx on opening 

 turns down its separate sepals close against the 

 stem in such a way as to form a sort of lobster- 

 pot, out of which the creeping insect can never 

 extricate himself. 



Inside the calyx-layer of five sepals comes 

 next the corolla-layer of five petals. These 

 petals, as we saw, are the attractive business 

 advertisement of the flower ; they contain at the 

 base of each a tiny honey-gland or nectary, 

 which is covered by a scale or small inner petal, 

 so to speak, to protect it from the attacks of 

 thievish insects. But when the bee or other 

 proper fertilising agent arrives at the flower, 

 he lights on the set of carpels in the very centre 

 of the blossom, and proceeds to go straight for 



