564 DICOTYLEDONES. 



ments when touched. Herbs, under-shrubs, less frequently shrubs. Goodenia, 

 Leschenaultia, Sccevola. 



Order 5. Stylidiaceae (or Candolleacese) ; 100 species, the majority 

 Australian ; zygomorphic flowers, hut with the ordinary position. The anterior 

 petal is very small. The chief characteristic feature is the presence of only 2 

 stamens (with extrorse anthers) which are united with the style and form a 

 stylar-column ; this is bent like a knee and sensitive at the bend to such a 

 degree that when touched it jerks violently across the flower to the opposite 

 side and then loses its sensitiveness. Herbs, less frequently mider-shrubs. 

 Stylidium (Candollea). 



Family 36. Aggregatae. 



The flowers, which are borne in "capitula" (Figs. 605, 610), 

 are epigynous (Fig. 605 C, D), 5-merou$ in the calyx, corolla and 

 andrcecium, the corolla is valvate in aestivation, with 2 carpels 

 (S5, P5, A5, Gr2). The anthers are united into a tube (syngene- 

 sious) (except Ambrosiea;} which surrounds the bifid style. There 

 is never more than 1 loculus in the ovary, with 1 erect, anatropous 

 ovule. The fruit is a 1-seeded nut (cypsela), with thin pericarp, 

 the calyx generally persists as a tuft of hairs (pappus) (Fig. 606) 

 on the summit of the fruit. Embryo without endosperm ; the 

 radicle directed downwards. 



Only 1 Order : Compositse. 



With respect to the inflorescence and the development of the 

 individual flowers, there is a very close resemblance to the Dipsa- 

 caceie, which stand on the same plane of progression as the 

 Composite. But while the latter are allied to Campanulinae as 

 the last stage in the process of evolution, the Dipsacacese form the 

 final stage of the Rubiales-Dipsacales. 



Order Compositae. (For the principal characteristics com- 

 pare those of the family.) The Compositae are chiefly herbs, 

 but trees and shrubs also occur in tropical countries. The leaves 

 may be scattered or opposite, but have no stipules. The outer 

 leaves of the involucre as a rule are barren, especially when 

 numerous and imbricate, while the innermost ones support the ray- 

 flowers of the capitulum ; in a few instances all are fertile (e.g. 

 Tragopogon, Tagetes). The CAPITULA are many-flowered, with the 

 exception, e.g. of Echinops, which has l-flow r ered capitula (see page 

 570). The capitula are again arranged in inflorescences, most fre- 

 quently corymbose with centrifugal order of development. The 

 form of the receptacle is an important character for the division of 

 the genera (flat, convex, conical), and also the presence of scales; 



