SEED-BEARING PLANTS 



501 



Of about 24,000 known species of monocotyledons, 

 over one-fourth are orchids. The number of individuals, 

 however, of any given species is small, as compared, for 



P 



-- c 



-- r 



FIG. 387. Floral organs of an orchid (Cattleya sp.). A, the entire 

 flower; sep, sepal; pet, petal; B, column, showing s, stigma and r t the ros- 

 tellum (beak), with the small glands at the tip; to the glands are attached 

 the four strap-shaped caudicles of the pollinia; C, pollinia, with the four 

 caudicles; below, the gland; D, longitudinal section of the column; p, 

 pollinium; E, the same, enlarged. (Cf. Fig. 386.) 



example, with the grasses. The most highly modified 

 forms are tropical, and are seen in temperate regions 

 only in plant-houses- 



