I.] EXPLANATION OF THE DEADNETTLE. 19 



them several rows of anthers (a). It might be sup- 

 posed therefore that the pollen from the anthers 

 would fall on and fertilise the stigmas. This, how- 

 ever, is not what occurs. In fact the stigmas come 

 to maturity first, and have lost the possibility of fer- 

 tilisation before the pollen is ripe. The pollen must 

 therefore be brought by insects, and this is effected by 

 small flies, which enter the leaf, either for the sake of 

 honey or of shelter, and which, moreover, when they 

 have once entered the tube, are imprisoned by the 

 fringe of hairs (//). When the anthers ripen, the pol- 

 len falls on to the flies, which in their efforts to escape 

 get thoroughly dusted with it. Then the fringe of 

 hairs withers, and the flies, thus set free, soon come 

 out, and ere long carry the pollen to another plant. 



Now let us return to our White Deadnettle and see 

 how far we can answer the questions which I began 

 by asking. 



In the first place, the honey attracts insects. If 

 there were no honey, they would have no object in 

 visiting the flower. The bright colour is useful in 

 rendering the flower conspicuous. The platform serves 

 as an alighting stage for bees. The length of the tube 

 has reference to that of their proboscis, and prevents 

 the smaller species from obtaining access to the honey 

 which would be injurious to the flower, as it would 

 remove the source of attraction for the bees, without 

 effecting the object in view. The upper arch of the 

 flower protects the stamens and pistil, and also presses 

 them firmly against the back of the bee ; so that, 

 when the bee alights on the stage and pushes its pro- 

 boscis down to the honey, its back comes into contact 



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