ANTHOPHTTA. 



269 



anther (representing one stamen), and this is on or near 

 the end of the column, so placed as to be readily touched 

 by an insect entering the flower. The pollen-cells cohere 

 in little sticky masses, which easily adhere to the head, an- 

 tennEB, or back of an insect. 



510. It is an interesting fact that in the ordinary terres- 

 trial Orchids the flower develops in such a way that it must 

 twist upon its ovary in order to attain its proper position 



Fig. 159.— An Orchid-flower (Orchis mascula) . A, vertical section of 

 a flower-hud (magnified) before it has twisted upon its ovary,/; gs, the 

 column, bearing a pollen-mass, pi; ft, its sticty disk, below which is the 

 stigma. B, an open flower ; /, its twisted ovary; I, lip ; ,sf, stigma ; a, 

 anther ; U, its sticky disk ; sp, spur. 



when open (Fig. 159). Thus, without twisting, the lip 

 {I) with its spur would be uppermost, while the anther 

 would be below. 



511. When a long-tongued insect is attracted to an 

 Orchid-flower by the color and odor, it thrusts its tongue 



