90 



PLAN OF THE FLOWER. 



[LESSON 13. 



(Fig. 176, 177) ; when the flowers are said to be dioecious (from two 

 Greek words meaning in two households). Or the two may occur 



on the same plant 

 or the same stem, 

 as in the Oak, 

 Walnut, Nettle, 

 and the Castor-oil 

 Plant (Fig. 178); 

 when the flowers 

 are said to be mo- 

 noecious (that is, in one household). A flower 

 may, however, be perfect, that is, have both 

 stamens and pistils, and yet be incomplete. 



242. Incomplete Flowers are those in which 

 one or both sorts of the floral envelopes, or 

 leaves of the blossom, are wanting. Some- 

 times only one sort is wanting, as in the 

 Castor-oil Plant (Fig. 178) and in the Anem- 

 one (Fig. 179). In this case the missing 

 sort is always supposed to be the inner, that is, the corolla ; and 

 accordingly such flowers are said to be apetalous (meaning without 

 petals). Occasionally both the corolla and the calyx are wanting, 

 when the flower has no proper cover- 

 ings or floral envelopes at all. It is then 

 said to be naked, as in the Lizard's- 

 tail (Fig. 180), and in the Willow. 



243. Our two pattern flowers (Fig. 

 168, 174) are regular and symmetrical 

 (239). We commonly 

 expect this to be the 

 case in living things. 

 The corresponding 



parts of plants, like the limbs or members of ani- 

 mals, are generally alike, and th<; whole arrange- 

 ment is symmetrical. This symmetry pervades 

 the blossom, especially. But the student may often fail to perceive 



FIG. 178. Monoecious flowers, i. e. one etaminate (s) and one pistillate (p) flower, of 

 the Castor-oil Plant, growing on the eamo stem. 



FJ<;. 17H. Aprt;ilous (incomplete) flower of Anemone Pennsylvania. 

 FIG. J80. A naked (but perfect) flower of the Lizanl's-tail. 



