INTERRELATIONS OF PLANTS AND ANIMALS 39 



and in sunny fields. The flower cluster 

 forms a tall and conspicuous cluster of 

 orange and yellow flowers. 



The corolla projects into a spur on 

 the lower side; an upper two-parted 

 lip shuts down upon a lower three- 

 parted lip. The four stamens are in 

 pairs, two long and two short. 



Certain parts of the corolla are more 

 brightly colored than the rest of the 



Flower cluster of " butter and 



flower. This color is a 

 guide to insects. But- 

 ter and eggs is visited 

 most by bumblebees, 

 which are guided by 

 the orange lip to alight 

 just where they can 

 push their way into 

 the flower. The bee, 

 seeking the nectar secreted in the spur, 

 brushes its head and shoulders against 

 the stamens. It may then, as it pushes 

 down after nectar, leave some pollen upon 

 the pistil, thus assisting in self-pollination. 

 Visiting another flower of the cluster, it 

 would be an easy matter accidentally to transfer 



Diagram to show how the bee pollinates " butter and eggs." 

 The bumblebee, upon entering the flower, rubs its head against the long pair of 

 anthers (a), then continuing to press into the flower so as to reach the nectar 

 at (AT) it brushes against the stigma (S), thus pollinating the flower. Inasmuch 

 as bees visit other flowers in the same cluster, cross-pollination would also be 

 likely. Why ? 



