498 



STRUCTURE AND LIFE HISTORIES 



386). One of the petals, the lip, presents a greater variety 

 of form in the various species than do the other petals. At 

 its base is the column, composed of the style, with which 

 are fused the one (or sometimes only two) stamens (Fig. 

 387). Except in the lady's slipper (Cypripediu m) , and its 



FIG. 382. Sabal palmetto. (In the right distance a barragona palm). 



Cuba. 



nearest relatives, the pollen adheres in masses or pollinia, 

 as in the milk-weed. The stalked pollinia adhere to visit- 

 ing insects, sometimes to their eyes, and are thus trans- 

 ferred from one flower to another. 1 



1 For details of the wonderful contrivances for cross-pollination, the 

 student should consult some larger treatise, such as Darwin's " Cross' 

 fertilization of Orchids.'* 



