680 



BOTANY 



PART II 



flowers is reduced. Stamens epipetalous. Ovary inferior, unilocular 

 with a single ovule. Fruit indehiscent. 



Family 1. Dipsacaceae. Herbs with opposite leaves. Flower with an epiralyx 



a c I* 



FIG. 766. Snccisa pratensis. a, Flower with cpiralyx ; 

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

 longitudinal section ; /, ovary ; hk, epicalyx. 



FIG. 767. Compositae. Floral 

 diagram (Canluus). 



which persists on the fruit. Tetramerous or pentamerous. Stamens 4, anthers 



free. Ovule pendulous, anatropous. Seed with endosperm. 



IMPORTANT GENERA. Dipsacus, the Teazel, lias recurved hooks on the involucral 



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



woollen cloth. Corolla with four lobes. Sitccisa (Fig. 766) has a four-lobed corolla ; 



bracts are present on the common recep- 

 tacle. Scabiosa has similar bracts but 

 has pentamerous flowers ; the marginal 



x-.. \ ^^^^^ *^!lf/ x flowers of the head are larger and 



dorsiventral. It is cultivated as an 

 ornamental plant. Knautia has tetra- 

 merous flowers ; no floral bracts. 



Family 2. Compositae ( C1 ). 

 For the most part herbs of very 

 various habit ; some tropical 

 forms are shrubs or trees. 

 Flowers actinomorphic or zygo- 

 C T& morphic with no epicalyx. 



|.-], ; . TilS. Arnica montana. a, Ray-flower; l>. Stamens five J anthers intrOl'SC, 

 dis-flower; e, the latter cut through longitudin- cohering by their Cuticles tO 

 ally. (After BERO and SCHMIDT, magnified.) , , , . , , , 



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. 770). Seed exalbuminous. The fruits are 

 achenes, often bearing at the upper end a crown of hairs, the pappus. 

 This corresponds to the calyx and aids in the dispersion of the 



a 



