536 



BOTANY OF THE LIVING PLANT 



outer short, the inner long, with black tips. These surround numerous 

 tubular disc-florets. Ray-florets are usually absent. The single disc-floret 

 consists of : 



Calyx, represented by numerous bristles (pappus), rising from the top of the 

 inferior ovary. 



Corolla, petals 5, gamopetalous, superior, rather longer than the pappus. 

 The five equal teeth are borne at the end of the corolla-tube, which is narrower 

 below and widens upwards into a bell. 



Androecium, stamens 5, epipetalous, alternating with the petals, inserted 

 by five distinct filaments on the throat of the corolla-tube at the point where 

 it dilates. Anthers united into a tube (syngenesious) . 



FIG. 442. 



I. Whole capitulum of Chrysanthemum. II. same in median section. III. disc- 

 floret in earlier (male) condition. IV. same in later (female) condition. V. ray- 

 floret. VI. style and stigma. VII. disc-floret in section. VIII. floral diagram. 



Gynoecium, carpels 2, syncarpous, ovary inferior, unilocular, with one 

 anatropous ovule. Style elongated, bearing in fully matured flowers two 

 ant ero- posterior lobes, which diverge beyond the tube of the anthers. 



Fruit, a brown striated nut, bearing the wide-spread pappus at the tip, 

 by means of which it is distributed by the wind. 



Pollination. If several flowering heads be examined from above it will 

 be seen that the flowers mature in acropetal succession, the oldest being outside. 

 The corolla bursts, the syngenesious and introrse anthers protrude, and the 

 pollen is driven out of them by the elongating style, the stigmatic lobes being 

 still appressed ; later these expand, exposing their inner receptive surfaces. 

 The flowers are thus protandrous. There is honey-secretion in the corolla- 

 tube, but the flowers are rarely visited by insects, and self-pollination is 

 certainly common. 



(43) The Ox-Eye Daisy (Chrysanthemum leucanthemum, L.), belonging 

 also to the Tubuliflorae, is a common perennial of dry ground (Fig. 442). The 

 capitulum is solitary on the end of a stem, which widens out to form the general 

 receptacle. From its margin arises the involucre of bracts, with membranous 

 margins. Within are numerous florets inserted on the receptacle, but without 



