306 BEES AND BEE-KEEPING. 



papilionaceous (butterfly) form (A, Fig. 65). It is 

 probable, that all flowers having an irregular corolla 

 are adapted to fertilisation by insects, and that the 

 latter are prevented, by the irregularity, from reaching 

 the nectary, except from that position which makes 

 their visits effective in securing a cross. In the 

 papilionaceous tribe, it frequently happens, that the 

 nectar-gatherer, in alighting, causes certain mechanical 

 changes by its weight, by means of which pollen is 

 transferred to its body for distribution to neighbouring 

 blossoms. In this order we find lucerne, sainfoin, 

 melilot, clover, vetches, and many others; but the 

 Pisum sativum (the kitchen pea), an importation from 

 Southern Europe, is an excellent typical flower, although, 

 singularly, in our own country, failing its native insect 

 attendants, it has acquired the power of self-fertilisa- 

 tion.* The corolla has five petals — a large upper one 

 (v)j the vexillum, or standard; two that are lateral, 

 the alae (a/), or wings ; and two, more or less united 

 at their lower margins, forming the keel, or carina, 

 which, within its boat-shaped cavity incloses the 

 stamens and pistil. The anthers are ten in number; the 

 filaments of nine of them (a, C) are confluent, form- 

 ing a covering for the ovary beneath and at the sides, 

 but slit above, where the tenth anther (a), with its 

 isolated filament, is placed. This slitting gives the bee's 

 tongue access to the nectar at n, B and C. The style is 

 somewhat hairy, while the anthers open early, and dis- 

 charge their pollen, which mainly lodges upon the 

 style. If the blossom of a pea, or vetch, be taken 



* Rev G. Henslow on « Self-fertilisation of Pkn^ r ( Tr^cdons^f 

 Lmnean Society, 2nd Series, vol. 1., page 361). 



