DICOTYLEDONOUS PLANTS 



225 



-with usually 5 stamens inserted on the corolla, the anthers 

 united into a tube which surrounds the style (Fig. 23, V). 

 Calyx with its tube adnate to the ovary, the limb sometimes 

 wanting, when present taking the form of scales, bristles, etc., 

 known as pappus (Pig. 24, II, III). Corolla either strap- 

 shaped (Pig. 25, r) or tubular (Fig. 23, V), in the former case 



anth 



,stig 



n 



ni 



Fig. ,23. —Bachelor's Button. 



I, vertical section of tlie receptacle ; II, style ^nd forked stigma (magnified) ; 

 m, corolla, united anthers and stigma (fnagnified) ; IV, pistil (magnified) ; 

 ,pap, pappus; aA;, akene; V, tubular flower cut vertically (magnified), showing 

 anther-tuhe, traversed by the style j i, lobe of coroUa. 



often 6-toothed, in the latter usually 6-lobed. Style 2-cleft 

 above. Fruit an akene, often provided with means of trans- 

 portation (Part II, Ch. XXIX). The largest family of 

 flowering plants and among the most specialized for insect 

 pollination. The genera of the northern United States are 

 divided into two suborders : I. TuBULiFLOB.ffi!, corolla of the 

 perfect flowers tubular and 5-lobed ; II. LiGtrLiFLOK.*;, corollas 

 all strap-shaped and flowers all perfect. 



