Obder to.— composite 453 



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

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

 long. Jl., Aug. 



21 C. discoidea Torr. & Gr. Glabrous, much branched, erect ; lys. 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.— (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. BrDENS, L. Bubr-Marigold, (La,t.bidens, 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 ; dist-flowers perfect ; receptacle chaffy, flat ; pappus of 

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

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



g Achenin linear, somewhat 4-flngled, 8 to 4-awned. Eays few or none No. 1 



§ Achenia flattened, broadest at top, — Rays 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, pinnatifid, rays very short or none ; outer invol. the length of the inner ; 

 ach. slender, elongated.--{i) Grows in waste places N. T. (Sartwell), Ct. (Robbma). 

 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) obsouye, obovate, 

 yellow rays. Jl. — Sept. 



2 _B. fronddsa L. Hda. discoid ; outer invol. 6 times as long as the flower, 

 its leaflets oiliate at base ; lower hs. pinnate, upper ones ternate, lanceolate, ser- 

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

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

 to every passer-by. St. 2f high, diffiisely branched. Lower lvs. in 2s 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 thorn the head, leafy; 

 ach. with 3 awns. — ® In swamps and ditches. Can. N. Sng., to Mo. St. 1 to 3f 

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

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



4 B. c^rnua L. nds. subradiaie, cernvmis; outer invol. as long as the flower; lvs. 

 aS simple, kaiceolate, subcoimate, dentate. — In swamps and ditches. Can. to Pa. 

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

 Branches opposite. Lvs. opposite, somewhat connate at base. Fls. 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 equal invol. ; 

 lvs. oblong, attemtate at each end, connate at base, dentate. — (J) A low plant, with 

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

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

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

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



6 B. B€ckii Torr. St. subsimple; submersed lvs. capillaceous-mvMifid ; emersed 

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

 than the involucre.— 1( In water, N. T. (Sartwell), &c. Tt. (Chandler), H. to 

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

 leaves dissected as in Eanunculus aquatilis ; upper 1 — 2' loiig, -J as vride, deeply 

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



59. ACMEL'LA, L. (Gr. ditiiri, 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 <tf the 



