COMPOSITE FAMILY 239 



100. COMPOSITE. COMPOSITE FAMILY 



Flowers epigynous, in a dense head, on a common recepta- 

 cle, surrounded by an involucre composed of many bracts 

 (Fig. 29), with usually 5 stamens inserted on the corolla, 

 the anthers united into a tube which surrounds the style. 



D 



FIG. 29. Flower cluster and flowers of yarrow 



A, flower cluster; B, section of flower cluster; (7, a ray flower; Z), a disk 

 flower, a, anthers ; ch, chaff of disk ; d, disk flowers ; o, ovary ; re, corollas 

 of ray flowers ; s, stigmas ; tc, corolla of tubular flower. (A, B, C, 1 times 

 natural size; D, 18 times natural size) 



Calyx with its limb sometimes wanting ; when present taking 

 the form of scales, bristles, etc., known as pappus (Fig. 30). 

 Corolla either strap-shaped (Fig. 29, re) or tubular (Fig. 29, tc) ; 

 in the former case often 5-toothed, in the latter usually 5- 

 lobed. Style 2-cleft above. Fruit an akene, often provided 

 with means of transportation. This is the largest family of 

 flowering plants and among the most specialized for insect 



