Obder 10.— COMPOSIT-^ 453 



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

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

 long. Jl., Aug. 

 21 C. discoidea Torr. &, Gr. Glabrous, much branched, erect ; Iva. temate, long- 

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

 cles ; outer involuere 3 — 5 linear-apatulate, leaf-like bracts ; ach. linear-oblong, 

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

 Stem and branches purplish. Terminal leaflets 3 — 5 by -J — IJ', lateral much 

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



58. BrOENS, L. Burr-Marigold, (Lat. ii'iejw, 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 obcomprcssed, obscurely quad- 

 rangular. — Lvs. opposite, incised. Fls. yellow. 



§ Achenia linear, somewhat 4-angled, 8 to 4-ftwned. Eaya few op none No. 1 



j Achenia flattened, broadest at top, — Eays none or very few Nos. 2—4 



— Eays about 8, showy, regular Nos. 6, 6 



1 B. bipinndta L. Spanish Needles. Smooth, lvs. bipinnate, Ifts. lanceo- 

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

 ach. slender, elongated. — (J) Grows in waste places K. Y. (Sartwell), Ct. (Robbins). 

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

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

 yellow rays. Jl. — Sept. 



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

 its leaflets ciUate at base ; lower lvs. pinnate, upper ones temate, lanceolate, ser- 

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

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

 to every passer-by. St. 2f high, diffusely branched. Lower lvs. in 23 or 5s. 

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

 Sept. 



3 B. connita "Willd. Hds. discoid, smooth; lvs. lanceolate, serrate, slightly 

 connate at base, lower ones mostly trifld ; outer scales longer than the head, leafy ; 

 ach. with 3 aims. — ® In swamps and ditches. Can. N. 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. c^rnua L. Sds. subradiate, cernuous; outer invol. as long as the flower; lvs. 

 aM simple, lanceolate, suboounate, 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. Pis. yellowish 

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

 Aug., Oct. 



5 B. chrysanthemoides L. Eays 3 times as long as the nearly eqtial invol. ; 

 lvs. oblong, attenuate at each end, connate at base, dentate. — (£) 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, comato bases. Flowers commonly erect, rays about 8, large, 

 spreading. ScaiiPly distinct from B. cernua. Sept., Oct. 



6 B. B^ckii Torr. St. subsimple; svhmersed lvs. capillaceous-multifid ; emersed 

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

 than the involuere. — y In water, N. Y. (Sartwell), &c. Vt (Chandler), N. to 

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

 leaves dissected as in Ranunculus .aquatilis; upper 1 — 2' long, i as wide, deeply 

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



59. ACMEL'LA, L. (Gr. dK/i?;, 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 ^ ; achenia compressed, those of the 



