CLASSIFICATION OF ANGIOSPERMS. 391 



of plants. In some cases the stems are fleshy, as certain species 

 of Senecio, and a few of the plants are aquatic. The leaves vary 

 in arrangement, being opposite (Fig. 270), alternate (Fig. 182) 

 or basal, and also in form and size. The most distinguishing 

 character is the inflorescence, which is a head or capitulum (Figs. 

 181, 242), consisting of i or 2 kinds of flowers, arranged on a 

 common torus, and subtended by a number of bracts, forming an 

 involucre. The flowers are epigynous and the fruit is an akene, 

 usually surmounted by the persistent calyx, which consists of 

 hairs, bristles, teeth or scales, which are known collectively as 

 the PAPPUS (Fig. 241). 



The individual flowers are called florets (Figs. 241, 242), 

 and may be hermaphrodite or pistillate, monoecious, dioecious or 

 neutral. Depending upon the shape of the corolla, two kinds of 

 flowers are recognized, one in which the corolla forms a tube, 

 which is 5-lobed or 5-cleft, known as tubular flowers (Figs. 

 241, C; 242, C) ; and one in which the petals are united into a 

 short tube, with an upper part that forms a large, strap-shaped, 

 usually 5-toothed limb, known as ligulaxe flowers (Figs. 241, 

 B;242,D): 



In some of the plants of the Compositse the head consists of 

 ligulate flowers only, but in the larger number of plants the head 

 is composed of both tubular and ligulate flowers or tubular flowers 

 alone and accordingly two main groups or sub-families are dis- 

 tinguished. The sub-family in which all of the flowers are lig- 

 ulate is known as Liguliflor.e, or Cichoriace^, by those who 

 give the group the rank of a family. This group includes plants 

 like dandelion, chicory, lettuce and Hieracium. The group or 

 sub-family in which the flowers are all tubular or ligulate on the 

 margin only, is known as the Tubuliflorjj. When the head 

 consists only of tubular flowers it is called discoid, but when 

 ligulate flowers are also present it is called radiate. When the 

 heads are radiate, as in the common daisy, the tubular flowers 

 are spoken of as disk-flowers, and the ligulate flowers as ray- 

 flowers. The disk-flowers are usually perfect, while the ray- 

 flowers are pistillate or neutral (without either stamens or pistils). 

 By some systematists the Tubuliflorae are divided into groups 

 which have been given the rank of families. This division is 



