302 BOTANY. [Ch. XVI 



the wing-petal is forced against the bee's side all dusted with 

 pollen. In the broom the pistil is rubbed on the centre of the 

 back of the bee. I suspect there is something to be made out 

 about the Leguminosae, which will bring the case within our 

 theory ; though I have failed to do so. Our theory will explain 

 why in the vegetable .... kingdom the act of fertilisation 

 even in hermaphrodites usually takes place sub jove, though 

 thus exposed to great injury from damp and rain." 



A letter to Dr. Asa Gray (September 5th, 1857) gives the sub- 

 stance of the paper in the Gardeners 1 Chronicle : — 



" Lately I was led to examine buds of kidney bean with the 

 pollen shed ; but I was led to believe that the pollen could 

 hardly get on the stigma by wind or otherwise, except by bees 

 visiting [the flower] and moving the wing petals : hence I 

 included a small bunch of flowers in two bottles in every way 

 treated the same : the flowers in one I daily just momentarily 

 moved, as if by a bee ; these set three fine pods, the other not 

 one. Of course this little experiment must be tried again, and 

 this year in England it is too late, as the flowers seem now 

 seldom to set. If bees are necessary to this flower's self- 

 fertilisation, bees must almost cross them, as their dusted right- 

 side of head and right legs constantly touch the stigma. 



" I have, also, lately been reobserving daily Lobelia fulgens 

 — this in my garden is never visited by insects, and never sets 

 seeds, without pollen be put on the stigma (whereas the small 

 blue Lobelia is visited by bees and does set seed) ; I mention 

 this because there are such beautiful contrivances to prevent 

 the stigma ever getting its own pollen ; which seems only 

 explicable on the doctrine of the advantage of crosses." 



The paper was supplemented by a second in 1858.* The 

 chief object of these publications seems to have been to obtain 

 information as to the possibility of growing varieties of 

 Leguminous plants near each other, and yet keeping them true. 

 It is curious that the PapilionaceaB should not only have been 

 the first flowers which attracted his attention by their obvious 

 adaptation to the visits of insects, but should also have consti- 

 tuted one of his sorest puzzles. The common pea and the 

 sweet pea gave him much difficulty, because, although they are 

 as obviously fitted for insect-visits as the rest of the order, yet 

 their varieties keep true. The fact is that neither of these 

 plants being indigenous, they are not perfectly adapted for 

 fertilisation by British insects. He could not, at this stage 

 of his observations, know that the co-ordination between a 



* Gardeners' Chronicle, 1858, p. 828. 



