198 



FOUNDATIONS OF BOTANY 



greatly modified leaf (Sect. 222), adapted into a seed- 

 bearing organ. Such a pistil may be one-seeded, as in 

 Fig. 166, or several-seeded, as in the diagrammatic one 

 (Fig. 150) ; it is called a carpel. The calyx and corolla are 

 also known as the floral envelopes. Flowers which have 

 the essential organs are called perfect flowers. They may, 

 therefore, be perfect without being complete. Incomplete 

 flowers with only one row of parts in the 

 perianth are said to be apetalous (Fig. 139). 

 209. Regular and Symmetrical Flowers. 

 A flower is regular if all the parts of 

 the same set or circle are alike in size and 

 shape, as in the stonecrop (Fig. 140). Such 

 flowers as that of the violet, the monkshood, 

 FIG. 139. Apetai- and the sweet pea (Fig. 141) are irregular. 



ous Flower of ^ . n 



(European) wild Symmetrical flowers are those whose calyx, 



corolla, circle of stamens, and set of 



carpels consist each of the same number of parts, or in 



which the number in every case is a multiple of the 



smallest number found in any set. The stonecrop is 



I II 



FIG. 140. Flower of Stonecrop. 

 I, entire flower (magnified) ; II, vertical section (magnified). 



symmetrical, since it has five sepals, five petals, ten sta- 

 mens, and five carpels. Roses, mallows, and mignonette 



