464 SYNGENESIA— POL.-FRUSTRAN. Centaurea. 



with the rudiments of a pistil only, abortive, lax, spread- 

 ing, often wanting, their slender tube gradually dilated 

 upwards, into an unequally funnel-shaped, very large 

 limb, with 5 or more sharp segments. Filam. in the flo- 

 rets of the disk only, capillary, very short. Anth, in a 

 cylindrical tube, about the length of the corolla. Germ. 

 in the florets of the disk, small, oblong. Style thread- 

 shaped, about equal to the stamens. Stigma with a pro- 

 minent, often cloven, point. The radiant florets have 

 only the rudiments of a germen^ with scarcely any style 

 or stigma. Seed-vessel none, except the permanent closed 

 calyx. Seed in the florets of the disk only, various in 

 shape, mostly very smooth. Doxim generally short, bristly, 

 or feathery, in some wanting, llecept. bristly. 

 A large herbaceous genus, which Jussieu, after Tourne- 

 fort, has divided into several, by the structure, or ter- 

 mination, of the calyx-scales. Linnaeus has kept it en- 

 tire, and as DeCandolle has not disturbed it, I shall 

 make no such attempt. Centaurea is most naturally allied 

 to Cardials^ Cirsium and Serratida, to one or other of 

 which some of its species might be referred, as differing 

 only in the presence of abortive, tubular, dilated, radiant 



Jlorets. But those with either simple or fringed calyx- 

 scales, whether furnished with an abortive radius or not, 

 must be kept separate. The presence of such a radius 

 is, in this case, an approach towards a double flower. 

 The leaves are either undivided, toothed, pinnatifid, or 

 pinnate; not spinous in any genuine species. Fl. erect, 

 terminal, or lateral, solitary, or corymbose ; red, blue, 

 yellow, or whitish. Cal. either unarmed, naked, beauti- 



. fully fringed, feathery, or unequally spinous. 



* Calyx-scales jagged, or fringed. 



1. C. Jacea. Brown Radiant Knapweed. 



Calyx-scales membranous, torn ; lower ones pinnatifid. 

 Leaves linear-lanceolate ; radical ones elliptic-lanceolate, 

 toothed. Flowers radiant. Seed-down very she4rt, in 

 a simple row. 



C. Jacea. Linn. Sp. PL 1 293. Fl. Suec. 300. MVld. v. 3. 2309. 



Comp. ed. 4. 140. Engl. Bot. v. 24. t. 1 678. Hook. Scot. 248. 



DeCand.Fr.v.4.9\. Bull. Fr. t. 227. Fl. Dan. t. 5\9. 

 Rhaponticum n. 195. Hall. Hist. v. 1 . 84. 

 Jacea. Tillands Ic.WX.f. 



