140 



PAKTICULAK FOEMS OF FLOWERS 



united in the center by the base of the style -tube, which 

 forms a cone-shaped body that separates from the torus 

 when the fruit is ripe. Do all of the ovaries develop, or 

 are some crowded out in the struggle for existence ? The 

 calyx is often reinforced by bracts, which look like an 

 extra calyx. These bracts form an involucre. An in- 

 volucre is a circle or whorl of bracts standing just below 



a flower or a flower - 

 cluster. The umbel of 

 wild carrot (Fig. 180) 

 has an involucre below 

 it. A large family of 

 plants, known as the 

 Malvaceae or Mallow 

 family, has flowers simi- 

 lar to those of the holly- 

 hock. To this family 

 belong marsh mallow, 

 althea, okra, cotton. Ob- 

 serve that even though 

 the hollyhock is a great 

 tall-growing showy plant 

 and the "cheeses" is a 

 weak trailing inconspic- 

 uous plant, they belong 

 to the same family, as 

 shown by the structure 

 of the flowers. 

 279. ORCHID FLOWERS. The flowers of orchids vary 

 wonderfully in shape, size, and color. Most of them are 

 specially adapted to insect pollination. The distinguish- 

 ing feature of the orchid flower, however, is the union of 

 stamens and pistil in one body, known as the column. In 

 Fig. 225 the stemless lady's -slipper is shown. The flower 

 is 3-raerous. One of the petals is developed into a great 



225. A lady's-slipper, to illustrate the 

 orchid family. 



