304 THE STORY OF PLANT LIFE 



The Compositse are found in all parts of the world. 

 The nearest allied orders are the Teasel group, 

 Valerian group, and Lobeliacese. 



Most of the Compositse are adapted to dry con- 

 ditions. Few, save Aster, Bidens, etc., are marsh or 

 aquatic plants, and very few are climbing plants. 

 None are epiphytes. 



Most of the plants are herbaceous and the order 

 includes very few shrubs or trees. The latter are 

 more or less characteristic of oceanic islands. 



The leaves are usually alternate, rarely opposite, 

 as in Bidens, etc., or in whorls, and radical in the 

 latter case. There are no stipules as a rule. The 

 root is frequently a tap root as in the Dandelion, but 

 it is tuberous in the Dahlia. There are oil-glands in 

 most types. In the Liguliflorse (see below), as in 

 the Dandelion, latex is present. 



The inflorescence is racemose, the flowers forming 

 spikes, or, more usually, heads or capitula. Thus, 

 the " flower " of the Daisy consists of not one 

 flower, but a large number of sessile florets borne 

 on a receptacle. The heads may form racemes, 

 corymbs, or compound heads. Around or below 

 each head is a whorl of bracts, or an involucre 

 answering the purpose of a common calyx (which 

 is usually replaced by pappus or bristles). This 

 protects the flowers in bud and the fruit before 

 dispersal. 



The receptacle is generally flat, convex, or spindle- 

 shaped, and is smooth, or hairy, and there are scaly 



