GAMOPETAL^— COMPOSITE 165 



two sorts of flowers. In the two Daisies the numerous central 

 flowers — termed the disk-flowers — are yellow; whereas the 

 marginal flowers — termed the ray flowers — form a single white 

 series immediately within the involucre. In the Sunflower the 

 conspicuous ray-flowers are yellow, and form a single series 



Fig. 208. — Vertical section of capitulum of Sunflower ; rc=receptacle of 

 inflorescence : /A = green bracts; ^=disk flower with style, arms already 

 protruding : a = younger disk flower, with anthers visible. 



surrounding the central brown mass composed of innumerable 

 little disk-flowers. 



The disk-flowers (figs. 210, 211). — Each flower is regular, 

 and has a tubular five-toothed corolla (cor\ within which succeed 

 five epipetalous stamens with united anthers (a) ; in the centre 

 is a gynsecium {ov, sy, sg) like that of the Dandelion-flowers. 

 There is no pappus in the two Daisies, but the calyx is re- 

 presented by epigynous scales (sep, s) in the Sunflower. Thus 

 in their general structure these flowers agree with those of the 

 Dandelion, but they differ from the latter in being actinomorphic. 



The ray-flowers (figs. 208 rf, 209), though superficially more 

 like the flowers of the Dandelion, are in reality constructed on 

 a different plan. Their calyx is absent in the case of the two 

 kinds of Daisies, but in varieties of the Sunflower there are 

 from one to five minute scales (ex). The corolla is tubular at 

 the base, and represents at this point five petals (judging by 

 comparisons with the other flowers) ; but above the tubular part, 

 the three more anterior petals grow out to form a long strap. 

 That the strap thus represents three petals is feebly denoted 

 by its terminal teeth in the Ox-eye Daisy, but is much more 



