ORDER 70. COMPOSITE 453 



branching plant, 1 to 2f high, with a panicle of large, showy, yellow heads. Lvs. 

 mostly opposite, thin, the upper 3-cleft, subsessile. Ach. i' long, awns half as 

 long. " JL, Aug. _ 



21 C. discoidea Torr. & Gr. Glabrous, much branched, erect; lv& ternate, long- 

 petiolate; Ifts. ovate-lanceolate, strongly dentate, hds. discoid on slender pedun- 

 cles; outer involucre 3 5 linear-spatulate, leaf-like bracts; ach. linear-oblong, 

 twice longer than the 2 erect awns which are hispid upwards. Ohio to La. 

 Stem and branches purplish. Terminal leaflets 3 5 by \ !', lateral much 

 smaller. Heads small (3" diam.), about 30-fiowered. Jl. Sept 



58. BrDENS, L. BURR-MARIGOLD, (Lat, Helens, two-toothed ; the 

 achenia have two (or more) barbed teeth.) Involucre double ; scales 

 somewhat similar, or the outer foliaceous ; rays 4 to 8 (sometimes 

 none), neutral ; disk-flowers perfect ; receptacle chaffy, flat ; pappus of 

 2 to 4 awns rough backwards ; achenia obcompressed, obscurely quad- 

 rangular. Lvs. opposite, incised. - xBte. yellow. 



Achenia linear, somewhat 4-ancrled, 8 to 4-awned. Rays few or none No. 1 



Achenia flattened, broadest at top, Eays none or very few Nos. 2 t 



Kays about 8, showy, regular. .' Nos. 5, 6 



1 B. bipinnata L. SPANISH NEEDLES. Smooth, Irs. bipinnate, Ifts. lanceo- 

 late, pinnatind, rays very short or none ; outer invol. the length of the inner ; 

 ach. slender, elongated. Grows hi waste places N. Y. (Sartwell), Ct. (Robbing). 

 St. 2 to 4f high, branching, smooth. Lvs. bipinnately dissected, nearly smooth. 

 IIJs. of flowers on long peduncles, each with 3 or 4 (or none) obscure, obovate, 

 yellow rays. JL-^-Sept. 



2 B. frondosa L. Hds. discoid ; outer invol. 6 times as long as the flower, 

 its leaflets ciliate at base ; lower Ivs. pinnate, upper ones ternate, lanceolate, ser- 

 rate ; ach. 2-awned. (D A common weed, in moist, cultivated fields throughout 

 Can. and U. S., often called Beggar-ticks from the 2-horned achenia which adhere 

 to every passer-by. St. 2f high, diffusely branched. Lower Ivs. in 2s or 5s. 

 FIs. in clusters at the end of the branches, without rays, yellow, leafy. Aug., 

 Sept. 



3 B. connata TVilld. Hds. discoid, smooth; Ivs. lanceolate, serrate, slightly 

 connate ct bate, lower ones mostly trifld; outer scaks longer than the head, leafy; 

 ach. with 3 awns. (T) In swamps and ditches, Can. X. Eng., to Mo. St. 1 to 3f 

 high, smooth and 4-furrowed, with opposite branches. Lvs. thin, taper-pointed, 

 often all undivided. Hds. scarcely ever with a ray. Aug. (B. tripartita, Bw.) 



4 B. cernua L. Hds. subradiate, cernuous; outer invol. as long as the flower; Ivs. 

 aU simple, lanceolate, subconnate, dentate. In swamps and ditches, Can. to Pa. 

 and Wise. St. 1 to 2f high, purplish, branched, round at base, striate above. 

 Branches opposite. Lvs. opposite, somewhat connate at base. Us. yellowish 

 green, finally drooping, generally with small yellow rays about 8 in number. 

 Aug., Oct. 



5 B. chrysaiitliemoidea L. Rays 3 tunes as long as the nearly equal invol. ; 

 Ivs. oUong, attenuate, at each end, connate at base, dentate. ,T) A low plant, with 

 large, yellow-rayed flowers, in muddy places. Can. and U. S. ' Stem 6 20' high, 

 round and smooth. Leaves smooth, with few remote teeth, narrow, opposite, 

 with narrow, connate bases. Flowers commonly erect, raya about 8, large, 

 spreading. Scarcely distinct from B. cernua. Sept.. Oct. 



6 B. Beckii Torr. St. subsimple; submersed Ivs. capiUaceous-muUifid ; emersed 

 ones lanceolate, connate, acutely serrate or lanciniate ; fis. radiate ; rays longer 

 than the involucre. Ij. In water, X. Y. (Sartwell), &c. Vt (Chandler), 1ST. to 

 Can. Stem 2 3f long, simple or with minute, slender branches above. Lower 

 leaves dissected as in Ranunculus aquatilis; upper 1 2' long, 4- as wide, deeply 

 serrate. Head solitary, terminal, yellow. July, Aug. 



59. ACHMEL'LA., L. (Gr. an\if\, a point; from the sharp taste of 

 the foliage?) Heads radiate; involucre shorter than the disk, double, 

 appressed, pubescent; receptacle, conical, chaffy; pales embracing the 

 flowers; rays about 12, ?, disk g ; achenia compressed, those of the 



