406 COMPOSITjE. Centaurea. 



head surrounded by large and leafy accessory bracts. — Carbeni, Adans. Fam. 

 ii. 116. Onicus, Gsertn., DC, not L. 



' C. BENEDfcTA, L. (Blessed Thistlb.) Low and branching annual, hirsute or pubescent : 

 leaves prominently reticulated, sinuate-piunatifld or laciniate-dentate, the teeth or margins 

 weakly pricldy ; lower attenuate at base ; upper narrowly oblong, partly clasping by broad 

 base : heads sessile, inch and a half liigh, equalled by the oblong involucral leaves : proper 

 involucre of thin-coriaceous bracts in few ranks, all or most of them abruptly tipped with an 

 aristiform or spinescent and pectinately prickly spreading appendage : receptacle very 

 densely setose with long and soft capillary bristles : coroUas light yellow : longer bristles of 

 the pappus alternating with inner and with the teeth of the akene. — Spec. ed. 2, ii. 1296 ; 

 Sibth. Flora Grseca, t. 906. Ciiicus benedicfus, L. Spec. ed. i. 826; Gsertn. Fruct. ii. t. 162; 

 DC. Prodr. vi. 606; Torr. & Gray, Fl. ii. 455. — Waste grounds, at seaports and elsewliere 

 near dwellings, in the Southern Atlantic States and in California; not common. (Nat. 

 from Eu.) 



§ 2. Centaurea proper. Akenes more or less compressed or quadrangular : 

 pappus of indefinite (either scanty or numerous) bristles or narrow palese : invo- 

 lucre globular or ovoid. 



* Old Wo]-ld species, sparingly naturalized, with comparatively small heads: scar or insertion of 

 akene lateral. 



■i~~ Bracts of the involucre (or some of tliem) armed with a rigid spine or prickle, and also more 

 or less spinulose along its sides or base: cartilaginous appendages terminating the anthers 

 commonly elongated and connate: ours annuals, none with the marginal corollas enlarged. — 

 Calciirapa, Juss. 



» C. CalcIteapa, L. (Star Thistle.) Low, much branched, diffusely spreading, green, gla^ 

 brate or hairy : leaves narrow, laciniate-pinnatitid ; uppermost somewhat iuvolucrate-crowded 

 at base of the sessile heads : principal bracts of the involucre becoming corneous, armed with 

 a widely spreading very long and rigid spine, which bears 2 or 3 spinules on each side at 

 base: corollas purple or purplish: pappus wanting. — Engl. Bot. t. 125; Torr. & Gray, Fl. 

 ii. 454. — Sparingly established at seaports from New York southward, chiefly as a mere 

 ballast-weed. (Xat. from Eu.) 

 C. solstitiAlis, L. Erect, a foot or two high, canescent with cottony wool : radical leaves 

 lyrate-pinnatifld ; cauline lanceolate and linear, mostly entire, decurrent on the branches in 

 narrow wings : heads naked, somewhat pedunculate : intermediate bracts of the globular in- 

 volucre tipped with a long spreading spine, having one or two spinules at base; outermost 

 bearing a few sm;;!! palmate prickles ; innermost only scarious-tipped : corollas yellow ; pap- 

 pus double; outer of short and squamellate, inner of longer bristles. — Engl. Bot. t. 243; 

 Reichenb. Ic. FL Germ. t. 795; Gray, Bot. Calif, i. 421. — Near San Francisco and Sau 

 Diego, California, sparingly introduced. (Nat. from Eu.) 

 C. Meliiexsis,L. Erect, 2 to 4 feet high, paniculately branched, cinereous-pubescent, some- 

 what woolly at first : radical leaves lyrate-pinnatifid ; cauline lanceolate or linear, mostly 

 entire, narrowly decurrent ou the branches : heads smaller, sessile or 1-2-leaved at base : 

 principal bracts of involucre bearing a spreading slender spine of about their own length, 

 which is pectinately spinulose towards its base ; innermost with simply spinescent tip ; outer- 

 most usually with the central spine reduced and the spinules palmate : corollas yellow : 

 pappus of very unequal rigid bristles or squamellai : akene lightly costate. — Sibtli, Flora 

 Grieca, t. 909; Reichenb. Ic, Fl. Germ. .xv. t. 796; Gray, Bot. Calif. 1. c — Fields, California 

 and Arizona, rather common. (Nat. from Eu.) 



■h- -I— Bracts of the involucre unarmed, most of them terminated by a scarious discolored fimbri- 

 ate-ciliate or lacerate appendage. — ./ncea, Platylophus, Cyanus, &o., Cass. 



++ Peri'uiiials, with rose-purple flowers: pappus obsolete. 

 "C. NfoKA, L. (Knapweed, Hardheads.) A foot or two high, branching, roughish-pubescent : 

 leaves lanceolate and entire, <ir lower sparingly toothed : most of the involucral bracts with 

 strongly pectiniilely ciliate-fringed bhu-ki.sh appendages, these only conspiciunis : flowers all 

 hermaphrodite, marginal ones not enlarged or rarely so. — Fl. Oaii. t. 606 ; Engl. Bot. t. 278. 

 — Fields, Newfoundland to E. New England. (Nat. from Eu.) 



