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 

 98, 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 (Ranunculacetz) 



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 gyncecium and sometimes 

 synonymous with carpel. (See 

 page 274.) When the carpels 

 are united into a single structure, 

 pistil is synonymous with gynce- 

 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. 1 13 A . — 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 98) ; 

 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 



