MOEPHOLOGY OF EEPHODUCTIVE ORGANS 181 



is more common to see the filaments united, and the anthers 

 free. This union by the filaments may gather them into one or 

 more bundles, the number being indicated by a Greek numeral 

 prefixed to the termination -adelphous. Thus, when all the 

 filaments unite together and form one bundle, as in the Mallow 

 (fig. 373) and Wood Sorrel (fig. 374), the stamens are said to 

 be monadelplious. When such a union takes place in a 

 complete flower, the coherent filaments necessarily form a 

 tube or ring round the pistil placed in their centre, as in the 

 Wood Sorrel (fig. 374) ; when the pistil is absent, and the 

 flower therefore incomplete, the united filaments form a more 

 or less central column, as in Jatroplia Curcas (fig. 375, a). 

 When the filaments unite so as to form two bundles, the 



Fig. 377. 



Fig. 376. 



Fig. 376. Diadelphous stamens of the Sweet Pea {Laihyrus odoratits), sur- 

 rouudiiig the simple pistil. There are ten stamens, nine of which are united 



and one free. Fig. 377. Flower of the Orange divested of its corolla, 



to show the polyadelphous stamens. 



stamens are termed diadelphous, as in the Pea (fig. 376), 

 Milkwort (fig. 341), and Fumitory ; the number of filaments 

 in each bundle may be equal, as in the Milkwort (fig. 341) 

 and Fumitory ; or unequal as in the Sweet Pea (fig. 376), 

 where there are ten stamens, the filaments of nine of them 

 being united to form one bundle, while the other filament 

 renaains free. The bundle in this case is made up of five 

 stamens belonging to one whorl and four belonging to the other, 

 the androecium in the Pea family being composed of two whorls 

 with five stamens in each. Wlien the stamens are united by 

 their filaments into three bundles, they are triadelphous, as in 

 most species of St. John's Wort (fig. 378) ; and when in more 

 than three, polyadelphous, as in the Orange (fig. 377). 



The union of the filaments in the above cases may either 



