1Y6 



THE SECOND BOOK OF BOTANY. 



is fertile, and placed behind the stigma, in the position 

 of the sterile stamen of the lady's-slipper. Examine 

 the pollen. Instead of being dry and powdery, you 

 find it pulpy-granular. In many orchids it coheres 

 into coarse grains, held together in one mass by cob- 

 webby tissue, and known aspollinia (Fig. 334). You 

 find just such pollen masses, or pollinia, in the gy- 



FIG. 334. FHJ. 835. 



nandrous stamens of the milk-weed (Fig. 335). The 

 ovary of the lady's-slipper is inferior, forming in fruit 

 a one-celled pod, with innumerable minute seeds borne 

 on parietal placentae. In some orchids you find it so 

 twisted as to alter the position of the petals. 



The characters of the Orchidacese will be better 

 understood by comparing them with other groups of 

 parallel-leaved plants. Provide yourself with lilies 

 of any sort, and specimens of blue-flag, or flower-de- 

 luce. Compare your lilies with the following de- 

 scription : 



Herbs with simple, sheathing or clasping, parallel- 

 veined leaves. Flowers regular, perfect. Perianth 



