202 



FOUNDATIONS OF BOTANY 



each other or distinct, or they may cohere by their fila- 

 ments into a single group, when they are said to be 

 monadelphous, of one brotherhood (Fig. 

 151), into two groups (diadelphous) (Fig. 

 152), or into many groups. In some 

 flowers the stamens are held together in 

 a ring by their coherent anthers (Fig. 

 153). 



216. Union of Pistils. The pistils 

 may be entirely separate from each 

 other, distinct and simple, as they are 



FIG. 144. -Bell-Shaped . _ t" 



corolla of Beii-Fiower in the buttercup and the stonecrop, or 

 (Campanula). several may join to form one compound 



pistil of more or less united carpels. In the latter case 

 the union generally affects the ovaries, but often leaves 

 the styles separate, or it may result 

 in joining ovaries and styles, but 

 leave the stigmas separate or at any 

 rate lobed, so as to show of how 

 many separate carpels the compound 

 pistil is made up. Even when there 

 is no external sign to show the 

 compound nature of 

 the pistil, it can usu- 

 ally be recognized 

 from the study of 

 a cross-section of the 



FIG. 145. Salver-Shaped 

 Corolla of Jasmine. 

 (Magnified.) 



FIG. 146. 



Wheel-Shaped Corolla 

 of Potato. 



ovary. 



217. Cells of the 

 Ovary ; Placentas. Compound ovaries are very com- 

 monly several-celled, that is, they consist of a number of 



