AGGREGATE. 569 



not rolled back, with fine hairs externally ; the stigmatic lines do not reach 

 beyond the centre, and do not meet together. Characteristic of Eiipatoiiiim, 

 Petasitfs, TusMago. C. The style is thickened beneath the stigtnatic branches 

 in the form of a knob, or very hairy (Fig. 609 C) ; the stigmatic lines reach as 

 far as the apex of the branches and then converge ; sometimes the stigmatic 

 branches are united as far as the apex. Characteristic of the Ci/iini-ete. D. 

 The stylar branches are lanceolate, or linear, pointed ; externally flat and 

 thickly covered with hairs in the upper portion; the stigmatic lines cease 

 where the hairs commence externally. Characteristic of Aster, T'ellix, Iintla, 

 Dahlia, etc. E. The stylar branches are linear, with long, brush-like hairs at 

 the apex, where they are either abruptly cut off or prolonged into a very hairy, 

 conical appendage ; the stigmatic lines are broad, reach as far as the brush-like 

 hairs, and do not meet together (Fig. 610). Characteristic of Senecio, Helian- 

 thus, Xanthium, Gnaphaliiim, Artemisia, Anthemix, and others related to these. 



A ring-like nectary is found round the base of the style. 



The thin-walled c-ypsela (Fig. 606), with, seeds fitting closely to 

 the pericarp, has many different forms (smooth, ribbed, spined, 

 etc.) ; its point of attachment generally lies at the lowest end 

 but sometimes it is drawn obliquely up the side (Centaurea, etc.). 

 The calyx, persistent on the apex of the fruit, has been described 

 above. Some genera have two or three different forms of fruits in 

 each capitulum. The embryo is straight, with the radicle turned 

 downwards, and without endosperm, but is rich in oil. 



The variously flowered capitula, whose normal tubular disc- 

 flowers have been changed to ligulate flowers, may be termed 

 " double flowers." 



The relationship of the Composite to the Catnpanulinse has been described 

 above (page 561). The alliance with the Dipsacacese is more apparent than 

 real. Similar capitate inflorescences also occur as the final stage in other lines 

 of descent, as in Eryiigium among the UmbeUiferce. 



i. Cynareae, Thistle Group. Flowers all $ , regular, with 

 tubular corollas. The receptacle is covered with numerous bristles, 

 which surround the flowers without any definite order, or the 

 edges of the grooves in which these are placed have a well-marked 

 fringe. The involucral leaves are numerous, imbricate, and are 

 either prolonged into a thorn or terminate with a membranous 

 edge. The style has been described on page 568 (Fig. 609 C). 

 Nearly all have a hairy or feathery pappus. The filaments are 

 sensitive. 



Carduus (Thistle) ; capitula ovoid ; involucral leaves compact, 

 imbricate, with thorny points ; the pappus-rays are hair-like and 

 united at the base by a ring (i.e. the calyx), and fall off together. 

 Cirsium (Fig. 608) has a feathery pappus, in other respects it 

 is like Carduus. C. arvense reproduces and passes the winter by means of 



