676 



BOTANY 



PART II 



free. Ovule pendulous, anatropous. Seed witli endosperm. The family is 

 wanting in the tropics and especially represented in the Mediterranean region and 

 in the Himalayas. 



Important Genera. — Dipsacus, the Teazel, has recurved hooks on the involucral 



a 



c 



f, 



Fig. 725. — Succisa pratensis. a, Flower with epicalyx ; 

 b, the same after removal of epicalyx ; c, fruit in 

 longitudinal section ; /, ovary ; hk, epicalyx. 



Fig. 726.— Compositae. Floral 

 diagram (Carcluus). 



and floral bracts. The capitula of D. fullunum are employed in the carding of 

 woollen cloth. Corolla with four lobes. Succisa (Fig. 725) has a four-lobed corolla ; 

 bracts are present on the common receptacle. Scabiosa has similar bracts but has 

 pentamerous flowers ; the marginal flowers of the head are larger and dorsiventral. 



It is cultivated as an ornamental 

 plant. Kii,au,tia has tetramerous 

 flowers ; no floral bracts. 



Family 2. Compositae ("'■^). 

 — Distributed over the whole 

 earth. For the most part hei'hs 

 of very various habit ; some 

 tropical forms are shrubs or 

 trees. Flowers actinomorphic 

 or zygomorphic with no epicalyx. 

 Stamens li\'e ; anthers introrse, 

 cohering by their cuticles to 

 form a tube which is closed 

 below by the unexpanded stigma. 

 The pollen is shed into the tube 

 formed by the anthers and is 

 swept out by the brush-like hairs of the style as the latter elongates. 

 The style is bifid above. Ovule erect, anatropous (Fig. 729). Seed 

 exalbuminous. The fruits are achenes, often bearing at the upi)er end 

 a crown of hairs, the j^appus. This corresponds to the calyx and 

 aids in the dispersion of the fruit by the wind (Figs. 72G-732). 

 The replacement of reserve starch by inulin is characteristic of the 

 Compositae. 



Fig. 727. — Arnica montana. a, Hay-llowpr; b, 

 disc-flower ; c, the latter cut througli longitudin- 

 ally. (After Berg and Schmidt, magnified.) 



