290 



FLOWERS 



Fig. 112. — Diagram of a 

 lengthwise section through 

 the flower of sweet pea ; /, 

 the one free stamen ; st, the 

 nine stamens whose fila- 

 ments are united. 



united carpels evolved from flowers 

 with separate carpels. (See Figure 

 g8, page 274.) 



A flower with separate carpels is 

 said to be apocarpous, while one 

 with united carpels is said to be 

 syncarpous. The flowers of the 

 buttercup family (Ranunculacece) 



are mostly apocarpous; besides 

 the buttercup, the anemone and 

 the hepatica are examples of this. 

 (See Figure 113 A .) 



As you have noted, the word 

 pistil is sometimes synonymous 

 with gynoecium and sometimes 

 synonymous with carpel. (See 

 page 274.) When the carpels 

 are united into a single structure, 

 pistil is synonymous with gynoe- 

 cium. When 

 the carpels are 

 separate, each 

 pistil is but 

 a single carpel, 



Fig. 113. — Section of a flower of 

 one of the mallow family, show- 

 ing the way in which the sta- 

 mens form a tube which incloses 

 the style. 



Fig. 113.4. — Mature 

 fruits which arise 

 from a single flower 

 of the anemone, a 

 flower with separate 

 pistils. The fruits 

 of hepatica are sim- 

 ilarly arranged. 



Thus we may define a 

 pistil as any structure composed of one or 

 more carpels which appears to be a single 

 organ. A pistil composed of one carpel 

 is called a simple pistil (see Figure g8) ; 

 one composed of more than one carpel is 

 called a compound pistil. In a compound 

 pistil the divisions or lobes of the stigma, 

 or the number of compartments of the 



