464 On the Fertilization of Papilionaceous Flowers. 



or black. It has been stated that a few of the white Haricots 

 in the rows adjoining the Negroes were in 1857 slightly affected. 

 Mr. Coe sowed some which were of a very pale brown, or cream- 

 coloured ; and he has sent me a pod produced this autumn, which 

 pod includes two beans of the above tint and one of a pale, dirty, 

 purplish brown. 



Now it may be asked, are we justified in attributing this extra- 

 ordinary amount of variation to crossing, whether or not the 

 crossing was all confined to the year 1857 ? or may not the case 

 be one of simple variation ? I think we must reject the latter 

 alternative. For, in the first place, the Negro Bean is an old 

 variety, and is reputed to be very true ; in the second place, I 

 do not believe any case is on record of a vast number of plants 

 of the same variety all sporting at the very same period. On 

 the other hand, the Negroes having been planted between rows 

 of white and brown beans, together with the facts which I have 

 given on the importance of insect agency in the fertilization of 

 the Kidney Bean, showing, as may be daily seen, how incessantly 

 the flowers are visited by bees, strongly favour the theory of 

 crossing. Moreover, the extraordinary increase in variability in 

 the second generation strikingly confirms this conclusion ; for 

 extreme variability in the offspring from mongrels has been ob- 

 served by all who have attended to this subject. 



As seed-raisers do not usually take any precautions in 

 separating their crops of leguminous plants, it may be asked, 

 how are we to account for the extraordinary amount of crossing 

 in Mr. Coe's plants in 1857, when almost every plant in the 

 four rows of the Negro seems to have been affected ? I may here 

 add that, in an old paper in the Journal of the Bath Agricultural 

 Society, there is an almost exactly parallel account of the crossing 

 of several varieties of the common Bean throughout a whole field. 

 Insect agency is always at work : but the movement of the co- 

 rolla will generally tend merely to push the flower's own pollen, 

 which is mature as soon as the flower is open, on to the stig- 

 matic surface ; and even if pollen is brought by the bees from 

 another flower, the chances are in favour of pollen from the 

 same variety being brought, where a large stock is cultivated. 



I can explain Mr. Coe's case, and that in the Bath Journal, 

 only on one hypothesis, viz. that from some cause the Negro 

 Beans did not, at Knowle, in 1857, produce good pollen, or 

 they matured it later than usual. This has been shown by Gart- 

 ner sometimes to occur, and would explain, with the aid of 

 insect agency, the whole case. Believing, as I do, that it is a law 

 of nature that every organic being should occasionally be crossed 

 with a distinct individual of the same species, and seeing that 

 the structure of papilionaceous flowers causes the plant's own 



