THE AMERICAN BOTANIST. 



113 



•usually borne at the top of the filament but in other cases 

 they are borne on the back of the filament in such a way 

 that one anther cell seems to be on each side of the fila- 

 ment. Occasionall3^, too, the top of the filament branches, 

 each branch being tipped with half an anther — that is, 

 one anther cell. Examples of this may be found in the 

 catalpa and in a majority of the plants in the mint family. 

 In the lily and certain other plants the anthers are bal- 

 anced on the very tip of the filament and seem able to 

 swing in any direction. 



The number of stamens is seldom less than five in five- 

 parted flowers or three in three-parted ones. In the mint 

 family with five-parted flowers there are usually four sta- 

 mens, in the four-parted flowers of the cress family there 

 are six stamens and in the three-parted flowers of orchids 

 there is often only one, but the majority of flowers have 

 as many or more stamens as there are petals, sepals or 

 pistils. When there are only as many , they are in a single 

 circle or whorl; when more they may be in two or more 

 whorls. The advantage of numerous stamens is shown 

 in the columbine where there are four or more whorls 

 which ripen in succession beginning with the outer whorl. 

 This enables each flower to supply fresh pollen a much 

 longer time than it could with a single whorl of stamens. 



The stamens are often assembled in groups as in some 

 of the St. John's-worts where they occur in three or more 

 tufts, or they ma^^ be formed into tubes and rings, la 

 the sunflower and others of its 

 tribe, the stamens are joined by 

 their anthers ; in the lobelia, an- 

 thers and filaments are joined in- 

 to a tube ; in the pea family nine 

 of the ten stamens are joined 

 (fig. 9, b) and in the mallow the 

 stamens are formed into a sort 

 of hollow column surrounding Fig.9. Forms of united stamens 

 the pistils (fig. 9, a). 



THE RECEPTACLE. 



In our conception of the flower as a modified branch, 

 we take the view that sepals, petals, stamens and pistils 



