THE FLOWER OF THE HIGPIER SEED-PLANTS 158 



really or apparently more or less united to each other. In 



Fig. 109 the stamens have arisen separately, but finally 



become joined together by their anthers 



(as is always the case in the family 



Compositce). In other cases the stamens 



appear united when they are not really 



so because they are borne on a ring or 



tube of tissue, as already explained in 



connection with the perianth (Sect. 180). 

 Without regard to whether the union 



is real or apparent, stamens which occur 

 in a single group 

 (the filaments appear- 

 ing joined) are said 

 to be monadelphous 

 (Fig. 110), in two 

 groups diadelphous 

 (Fig. Ill), in va&Qj gioM^s, polyadelphous 

 (the terms meaning one brotherhood, 

 two brotherhoods, many brotherhoods). 

 182. The CarpeL — The simplest form 

 of the organ which bears the structures 

 called ovules that are to mature into 

 seeds is known as the carpel. 



In the lowest of the two great groups 

 a Thistle, with An- ,, , , ^ ,, b b r 



thers united into a of seed-plants, the gymnosperms (mean- 

 Ring, ing naked seeds), to which the pines, 

 a, united anthers; spruces, cedars, and the like belong, the 



/, filaments, hearded ovules are bome exposed on the surface 

 on the sides. 



of the carpel, which usually has the form 



of a scale. But in the higher group of seed-plants, the 



angiosperms (meaning seeds in a vessel) the carpels develop 



A B 



Fig. 108. Parts of 

 a Stamen. 



^, front; 5, back, a, 

 anther; c, connect- 

 ive ; /, filament. 



Fig. 109. Stamens of 



