PHANEROGAMIA 



681 



fruit by the wind (Figs. 767-773). The replacement of reserve 

 starch by inulin is characteristic of the Compositae. 



The individual flowers are either radially symmetrical with a five-lobed corolla 

 (Fig. 768 b, c) or they are two-lipped as in the South American Mutisieae, the 



FIG. 769. Longitudinal section of capitulum a, of Lappa major with floral bracts ; 6, of Matricaria 

 Chairwmilla without floral bracts. (After BERG and SCHMIDT, magnified.) 



upper lip having two teeth, the lower three. By suppression of the upper lip 

 flowers with a single lip are derived ; such flowers exhibit three teeth at the tip (Fig. 

 768 a). The ligulate flowers (e.g. of Taraxacum, Fig. 775) are similar in general 

 appearance to the latter ; the corolla is here deeply split on one side and its 

 margin bears five teeth. In addition to those Compositae which have only 

 ligulate or only tubular florets in 

 the head, there are many which have 

 tubular florets (disc-florets) in the 

 centre, surrounded by one - lipped 

 florets (ray - florets) (Fig. 769 b). 

 These usually differ from one another 

 in sex as well as in colour ; the disc- 

 florets are hermaphrodite, the ray- 

 florets purely female. The flower- 

 heads are thus heterogamous (Matri- 

 caria, Arnica). Lastly, the marginal 

 florets may be completely sterile 

 (Centaurea Cyanus) and serve only 

 to render the capitulum conspicuous 

 to insects ^ I0- ^"^- Arnica montana. a, Receptacle of capi- 



, ,. .,. tulum after removal of fruit; h, fruit in longi- 



Important sub-families and genera. tudina , 8ectfon> the pappl]8 on , y partly shown 



1. Tiibulifiorae, the heads contain only (After BERO and SCHMIDT, magnified.) 

 tubular florets : (a) Cynareae. The en- 

 larged axis of the inflorescence or common receptacle has setaceous floral bracts ; 

 the involucral leaves form several series and are prickly or have membranous 

 margins. The flowers are either all hermaphrodite or the marginal florets 

 are sterile. Style swollen below the stigmas into a cushion-like ring. Fruits 

 with a pappus. Carduus (Plumeless Thistle), pappus of simple, hair-like bristles. 

 Cirsium, with feathery pappus. Echinops, with single-flowered capitula associated 



