VARIATIONS IN STRUCTURE 



289 



- Types of anthers, showing various ways 

 in which pollen is discharged. 



Sweet peas and clover belong to the same great family 

 (Leguminosce) , and this arrangement of stamens occurs in 

 the flowers of very 

 many members of 

 that family. (See 

 Figure 112.) An- 

 other great group of 

 plants is character- 

 ized by the fact that 

 the stamens form a 

 tube which closely 

 surrounds the pistil. 

 From this tube the 

 stamens branch out fig. ho 

 irregularly and in in- 

 definite numbers. The common mallow, the hollyhock, the 



hibiscus, and the cot- 

 ton plant are members 

 of this group. (See 

 Figure 113.) 



E. Variations of the 

 Gyncecium. — The car- 

 pels are usually united, 

 while some flowers, as 

 these of the pea fam- 

 ily, have only one. 

 Many flowers, how- 

 ever, have separate 

 carpels, and this con- 

 dition is known to be 

 more primitive than the united condition. Flowers with 



Fig. hi. — Flower of morning-glory (Jpomea 

 purpurea), showing a sympetalous corolla and 

 the attachment of the stamens to it. 



