THE ANGIOSPERMAE 



1311 



{a) Flowers sought after for Pollen (see also p. 1260) 



It has already been pointed out that the majority of insects visit flowers 

 chiefly to obtain nectar. The insect may use this nectar personally, like a 

 butterfly, or it may gather the nectar, carry it away to its nest, and use it to 

 feed its young, as is done by the bees. Among the latter, however, the grubs 

 and the adult workers are not nourished exclusively on nectar, they require 

 a supply of protein and this is provided by pollen, which contains 7-26 per 

 cent, of protein. Thus we find that, where the grub depends upon the 

 parent insect for its food, as opposed to a caterpillar which finds its own, 

 pollen, as well as nectar, is supplied. 



I. Actinomorphic and Other Open Flowers 



These flowers are often simple and regular in form and many open early 

 in the year at the time when the young grubs have been hatched after the 

 winter rest period. Examples of such flowers are Anemone, Thalictriim, 

 Papaver, Hypericum, Helianthemum, and Verbascum in all of which the 

 pollen is abundant and very freely exposed. 



Fig. 1 23 1. — Verbascum blattario. A, Part of an inflorescence. B, 

 Flower in longitudinal section sho\\ing the three " fodder 

 stamens '" with hair\' filaments. C, Single stamen. 



Such flowers may provide sugary juices and occasionally nectar as well, 

 but on the whole nectar appears to be a secondary consideration and is often 

 entirely absent. Indeed pollen is sometimes gathered by bees from flowers 



