Wild Flowers as They Grow 



is plentiful and stored away in a sac enclosing the 



ovary, its proboscis being guided there by two 



parallel lines of hairs, like railway lines, running 



towards it. Although weU in the flower its great 



body prevents the lips from quite closing behind it, 



and while it sips the honey its back rubs on the 



roof as it almost fills the cavity. But up in the 



roof, their four filaments running along it like 



parallel beams, are the pollen boxes, and these 



open and pour out the yeUow dust on to the back 



of the insect. Another column, the receptive column 



from the ovary, lies among the stamen filaments, 



and no doubt this gets dusted with pollen from 



the bee's back — either its own flower's pollen or 



that from a neighbour. Darwin experimented and 



found that, in the crimson-coloured Snapdragon, 



pollen from the stamens of its own flower could not 



fertilise it at all, but that in the white varieties it 



might possibly, though not very readily, do so. 



Anyway, no doubt cross-fertihsation is the usual 



procedure. Finally, the available honey being 



136 



