766 THE SUBDIVISIONS OF THE VEGETABLE KINGDOM. 



flowers have fallen off The number of flowers in a capitulum varies greatly. In 

 many species several hundreds of flowers (florets) are crowded together, in Adeno- 

 styles and Eupatorium (see p. 320, fig. 294 ^) there are only a few flowers in each 

 capitulum, and in Echinops it is limited to a single one. The capitulum is sur- 

 rounded by an involucre of bracts crowded together. The form of these involucral 

 leaves exhibits extreme variety. In Thistles their apices are transformed into 

 prickles, in the species of the genus Xeranthemum, Helichrysum, &c., they are like 

 paper or parchment, dry, and distinguished by white, yellow, violet, and red colours. 

 They preserve these characteristics unchanged even when dried, and can therefore 

 be made up into bouquets and wreaths which do not fade. These composite flowers, 

 which are known as " immortelles ", are everywhere used as symbols of immortality 

 and as memorial tokens. The Cape is exceptionally rich in Everlasting Flowers; 

 among the species found there is Helichrysum eximium. The Edelweiss {Gnaphalium 

 Leontopodium, see vol. i. p. 315, fig. 76) may also be looked upon as an immortelle, 

 although here the bracts are not themselves dry and membranous, but are only 

 covered with a dry, white felt of hairs. In many species the capitula are themselves 

 grouped in capitula or glomerules. One of the most striking instances of this is 

 afforded by the species of the genus Haastia, which are shown on p. 188. In the 

 genus Echinops a large number of one-flowered capitula are grouped together in 

 spherical heads, usually of a steel-blue colour. The capitula often look like single 

 flowers, and in former times they were looked upon by botanists as compound 

 flowers {flores compositw), whence the name of Compositse. In many species, e.g. the 

 Sun-flower (Helianthus annuus), the capitula attain to a diameter of 40 centi- 

 metres. In the actinomorphic corollas a tube and a bell-shaped 5-partite limb may 

 be distinguished (see p. 360, figs. 302 1- ^' ^). The zygomorphic flowers are either two- 

 lipped, the upper lip being composed of one or two petals, and the under lip of four 

 or three petals, or else ligulate, in which case the tube is greatly abbreviated and 

 the free end of the ligule usually exhibits five segments or teeth (see p. 121, fig. 222*, 

 and p. 236, fig. 261 ^). In Valerianacese the corolla is usually produced on one side 

 into a kind of sac, which in the genus Valeriana is short and blunt (see p. 289, 

 fig. 283 '), and in the genus Centranthus is in the form of a long, slender, pointed 

 spur (see p. 240, fig. 263 ^ and p. 306, figs. 289 ^' ^). In the capitula of Compositse the 

 flowers with tubular, ligulate, and bilabiate corollas respectively are grouped to- 

 gether in a great variety of ways. It is not common for all the flowers of a capitu- 

 lum to have tubular flowers, but that is sometimes the case (e.g. Eupatorium, 

 p. 320, fig. 294^); much more frequently all the fiowers in a capitulum have ligulate 

 corollas (e.g. Hieracium, p. 112, fig. 222 ^), and in the majority of instances the 

 flowers in the middle of the capitulum are furnished with tubular corollas, and 

 those near the periphery with ligulate or bilabiate corollas (see p. 360, fig. 302 ^). 

 The distribution of the sexes has been dealt with on pp. 295-297, and pp. 318-321. 

 In the Compositse the anthers of the five stamens are united into a tube. The 

 anthers are not connate in the other families. In Dipsacese the androecium consists 

 usually of four stamens, and in "Valerianacese usually of three stamens (see. p. 289, 



