96 Flowers and their Unbidden Guests. 



clamber over the trellis, and get inside the flower 

 through the central entrance, then they must neces- 

 sarily come in contact with the stigma, and in due 

 succession with the anthers.-^ 



In the cases with which we have been dealing it 

 is the corolla that is split up into a fringe. But 

 in many other flowers it is the margin of the calyx 

 that is thus fringed, or that is beset with hair7like 

 trichomes which prevent insects from getting at the 

 nectar by back-doors, and direct them to the main 

 entrance, where anthers and stigma are placed to meet 

 them. I purposely select a very inconspicuous small 

 flower, Alyssum calydrmm (Plate I. fig. 40, flower seen 

 from above), as an example of this frequently recurring 

 arrangement. The segments of the calyx are here sepa- 

 rated by deep fissures, which reach almost to its base, 

 and inasmuch as the clawg of the petals which stand 

 in front of these fissures only close them imperfectly, 

 it would have been possible for very small insects, that 

 had settled on the stem, or had crawled up from the 

 ground, to creep in through these lateral clefts and so 

 get at the nectar. But the hair-like trichomes which 

 grow on the convex surface of the sepals interdigitate 

 repeatedly with each other, and form a lattice-work in 

 front of the clefts, their free points reaching as far as 



1 I saw the small beetle Meligethes eaalis fecundate a, flower of 

 Oentiana cilicUa, after it had been compelled by the " weel " to get 

 in at the central entrance, which brought it into direct contact 

 with the mature stigma. 



