THE COROLLA 



215 



307. The Ligulate, or strap-shaped corolla, seen in the 

 rays of the sunflower family, is of such frequent occurrence 

 as to deserve a special examination. If 

 you will remove one of the small blos- 

 soms from the disk of any large composite 

 flower (Fig. 426) 

 and imagine its 

 corolla greatly en- 

 larged and split 

 open on the inner 

 side, you will get 



a very good idea of 426. A head of artichoke 427."^ A ray flower of 

 the nature of the flower divided lengthwise. artichoke, enlarged. 



rays. The five little teeth into which it is usually cleft 

 at the top show the number of lobes or petals of which 



it is composed. The corolla of the lobelia 

 St.. ^f^ ysstv- ?t represents an intermediate state between 



the tubular and ligu- 



& T late forms (Fig. 429). 



308. Bilabiate Co- 

 rollas. By far the 

 most important and 

 widely distributed of 

 sympetalous corollas 

 is the bilabiate, or 

 two-lipped kind, dis- 

 tinctive of the mint 



428. A vertical 

 section of a disk flower, 

 showing the divided 

 style, st, and the sta- 

 mens, s, s, with their 

 anthers united (syn- 

 genesious) . 



429. Flower of Lobelia 

 cardinalis, with tube of 



corolla divided on one d figwort f am il ies 



side; filaments and an- 



thers united into a tube 



(after GRAY) : / tube of 

 filaments; a, anthers. 



and their allied 

 groups, numbering in 

 all over six thousand 

 known species. They are of many varieties, from the 

 scarcely perceptible irregularity of the verbena and mullein 

 to the complicated structures of the sage, snapdragon, and 

 toad flax. Two of them are so strongly marked that 

 they have received special names. These are the ringent, 

 or open-mouthed, and the personate, or closed (Figs. 430 



