460 Mr. C. Darwin on the Agency of Bees 



stigma, it is quite possible that the fertilization of the covered- 

 up flowers might have been thus aided. 



In the common Bean there is no such obvious relation between 

 the structure of the flower and the visits of bees ; yet, when these 

 insects alight on the wing-petals, they cause the rectangularly 

 bent pistil and the pollen to protrude through the slit in the 

 keel-petal. I was led to try the effect of covering them up, from 

 a statement in the ' Gardeners' Chronicle' made several years ago, 

 viz. that when bees bite holes through the calyx of the flower in 

 order to get more easily at the nectar, the crop is injured. This 

 was attributed by the writer to injury of the ovarium, which I 

 am sure is incorrect. But I thought that it was possible that 

 the fertilization would be less perfect, as soon as bees ceased to 

 alight on the wing-petals. I accordingly covered up seventeen 

 plants, just before the flowers opened, moving a few flowers to 

 ascertain that very fine pods, including the full average number 

 of beans, could be, and were, produced on the plants under the 

 net. These seventeen plants produced thirty -six pods ; but no 

 less than eight of them, though well formed, did not include a 

 single bean. The thirty-six pods together contained only forty 

 beans, and, if the empty pods be excluded, each produced on an 

 average less than one and a half beans; on the other hand, 

 seventeen uncovered plants in an adjoining row which were 

 visited by the bees produced forty-five pods, all including beans, 

 135 in number, or on an average exactly three beans to each 

 pod, — so that the uncovered beans were nearly thrice as fertile 

 as the covered. 



In an old number of the 'Gardeners' Chronicle' an extract is 

 given from a New Zealand newspaper, in which much surprise is 

 expressed that the introduced Clover never seeded freely until 

 the hive-bee was introduced. This statement may be erroneous ; 

 at least, as I shall immediately show, it does not apply to the 

 Canterbury Settlement. But I was induced by it to cover up 

 under the same open sort of net about a yard square of the 

 common White Clover, growing thickly in turf; and I then 

 gathered an equal number of heads from the covered and from 

 some uncovered plants which were growing all round, and which 

 I had seen daily visited by my bees. I collected the seed into a 

 small parcel ; and, as far as I could estimate, the uncovered plants 

 produced just ten times as much seed as the covered. Speaking 

 loosely, the covered heads might have been said to have produced 

 no seed. 



Lathyrus grandiflorus is very rarely visited by bees in this 

 country ; and from experiments which I have tried during the 

 last two summers, and from experiments recorded in ' Loudon's 

 Magazine/ I am convinced that moving the flowers favours their 



