Bidens. COMPOSITE. 295 



lineatis," &c., is taken) & Vaill. ; Walt. Car. 215; name best not restored. Dtodonta mitis, 

 aurea, & leptophijlla, Nutt. Trans. Am. Phil. Soc. 1. c. 360. — Wet cjround, Virginia to Florida. 

 The original C. aiirea is a form with some of the upper leaves lanceolate and entire, low- 

 ermost of 3 leaflets. Extreme forms are : var. snb/ntef/ra, Torr & Gray, with all or most of 

 the leaves undivided and lanceolate ( C. ar(/uta,' Vursh, Fl. 567, & C ambiaiia, Nutt. Jour. 

 Acad, rhilad. vii. 75) ; var. leptophijUa, Torr. & Gray, 1. c, with leaves or their few divisions 

 elongated linear, only a line or two wide (Dwdonla leptophijlla, Nutt. T^'ans. Am. Phil. Soc. 

 1. c), a brackish coast form; and var. incisa, Torr. & Gray, 1, c, with nearly all the leaves 

 3-7-divided and the divisions incised or coarsely serrate ( C. mMs, Michx. Fl. ii. 138, & the 

 C. coronata of herb. Linn.), the form which approaches or passes into the following. 

 C. trichosperma, Micnx. Glabrous or nearly so, a foot or two (rarely 3 to 5) high: 

 leaves almost all 3-5-divided into lanceolate coarsely serrate or pinnately incised divisions : 

 rays oval-obovate, two-thirds to three-fourths inch long : akenes narrowly cuneate-oblong, 

 sparsely hairy or glab'rate, about 4 lines long and barely a line wide, or the outer somewhat 

 broader and shorter, bearing a pair of strong subulate pointed erect teeth, commonlv equal 

 in length to the breadth of the summit of the akeue. — Fl. ii. 130 ; Torr. & Gray, Fl.'ii. 340. 

 V.aurea, Lindl. Bot. Reg. t. 1228. Diodonta coronata, 'Nutt. I. c. — Wet ground, coast of 

 Mass. to Virginia and N. E. Georgia. Also shore of L. Erie to Illinois ; where is a 



Var. tenuiloba. Tall, much branched : di visions of the leaves from narrowly lanceo- 

 late to linear : akenes smaller (outer barely 3 lines long), and with shorter somewhat spread- 

 ing teeth : approaching C. aurea. — Peat bogs, Indiana and Illinois, Vasei/, Stewart, &c. 

 -1— -t— Heads radiate: rays golden yellow, sometimes inch long: akenes obovate, very flat, with 



very thin margins hispid-ciliate : leaves all 3-7-divided or parted; the divisions serrate, incised, 



or some agam cleft: herbage somewhat pubescent or glabrous. (Hybrids of these with Bidens 



fronuvsa or others are not uncommon.) 



C. aristosa, Michx. Stem 1 to 3 feet high : divisions of the leaves lanceolate, acuminate : 

 bracts of the outer involucre 8 to 10, barely ciliate, not surpassing the inner: akene with a 

 pair of slender upwardly scabrous awns of 'ts own length, or these rarely wanting. — Fl. 

 ii. 140; Torr. & Gray, 1. c. ; Hook. f. Bot. Ma^r. t. 6462. C. aristata, Willd. Spec. iii. 22.53. 

 Diodonta aristosa, Nutt. I.e. — Swamps, Michigan to Iowa, Missouri and W. Louisiana: 

 Southwestward with the var. miittca (the awns wanting), there disposed to pass into the 

 next. 



C. involucrata, Nutt. Heads rather larger : bracts of the outer Involucre 12 to 20, mostly 

 surpassing the inner, slender, hispid on the back and margins : akenes with 2 short acute 

 teeth. — Jour. Acad. Philad. vii. 74 ; Torr. & Gray, 1 c. Diodonta involucrata, Nutt. Trans. 

 Am. Phil. Soc. 1. c. — W. Illinois to Kansas and Texas. 



-i— -1— -)— Heads without rays, or rarely a rudimentarj' one, short-pednnculate: disk dull j'ellow : 

 outer involucre of 3 to 5 irregular foliaceous bracts, some or most of them surpassing tiic head: 

 herbage glabrous or nearly so: leaves slender-peti.iled. 



C. bidentoides, Nutt. Rather stout, 1 to 4 feet high, with ascending branches : leaves 

 undivided, lanceolate, acuminate, serrate, tapering at base into the long petiole : heads ob- 

 long, half to three-fourths inch long, and outer involucrat bracts sometimes inch and a half 

 long, resembling uppermost leaves ; bracts of inner involucre with somewhat petaloid mar- 

 gins and tips • akenes cuneate-linear, 4 or 5 lines long, more or less exceeding the two setiform 

 upwardly hispidulons awns, rarely vestiges of awns from lateral nerves. — Torr «fc Gray, Fl. 

 ii. 339. Diodonta (Ileterodonta) bidentoides, Nutt Trans Am. Phil Soc. vii 361. — Muddy 

 shores of Delaware River and Bay, from above Philadelphnx. first coll by NuttaU. 



C. discoidea, Torr. & Gray, 1. c. Slender, with widely spreading branches, a foot or two 

 high: leaves membranaceous, irregularly serrate; uppermost undivided and ihomboid- 

 lanceolate ; lower divided into 3 sessile or petiolulate leaflets : heads campanulate, a cpiarter- 

 inch high : akenes narrowly cuneiform, 2 or 3 lines long, the two subulate teeth rather than 

 awns mostly shorter than the width of its summit. — River borders and swamps, Connecticut 

 and N. New York to Ohio, Virginia, and Texas. 



113. BfDENS, Tourn. Bur-Marigold, (Lat h'dens, with two teeth or 

 prongs: name from the adjective, i. e. planfa bidens, therefore feminine.) — Herbs, 

 of wide distribution, chiefly American; with opposite either simple or compound 



