Bidens. COMPOSITE. 295 



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

 aiirea, & leptopkylla, Nutt. Trans. Am. Phil. Soe. 1. c. 360. Wet ground, Virginia to Florida. 

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

 ermost of 3 leaflets. Extreme forms are : var. subinttyra, Torr & Gray, with all or most of 

 the leaves undivided and lanceolate ( C. nnjuta, Pursh, Fl. 567, & C. <i<nbiuna : Xutt. Jour. 

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

 elongated linear, only a line or two wide (Diodonta leptopliylla, Nutt. Trans. 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. mitis, Michx. Fl. ii. 138, & the 

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

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

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

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

 sparsely hairy or glabrate, 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, commonly equal 

 in length to the breadth of the summit of the akene. Fl. ii. 139 ; Torr. & Gray, Fl. ii. 340. 

 C.ditmt, Liudl. Bot. Reg. t. 1228. Diodonta coronata, Nutt. 1. c. Wet ground, coast of 

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



Var. teiiuiloba. Tall, much branched : divisions 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. aurca. Peat bogs, Indiana and Illinois, Vasey, 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 again cleft: herbage somewhat pubescent or glabrous. (Hybrids of these with Bidens 

 fronctosa 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, l.'c. ; Hook. f. Bot. Mag. t. 6462. C. aristata, Willd. Spec. iii. 2253. 

 Diodonta aristom, Nutt. 1. c. Swamps, Michigan to Iowa, Missouri and W. Louisiana : 

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

 next. 



C. involucrata, NUTT. Heads rather larger : bracts of the outer involucre i2 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. 



H -IT- -i Heads without rays, or rarely a rudimentary one, short-pedunculate: disk dull yellow: 

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

 herbage glabrous or nearly so: leaves slender-petioled. 



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 involucral 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 sctiform 

 upwardly hispidulous awns, rarely vestiges of awns from lateral nerves. Torr & Gray, II. 

 ii. 339. 'Diodonta (Hetcrodonta) bidentoides, Nutt. Trans. Am. Phil. Soc. vii 361.- -Muddy 

 shores of Delaware River and Bay, from above Philadelphia, first coll by Nuttall. 



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

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

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

 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. BlDENS, Tourn. BUR-MARIGOLD. (Lat foYfens, with tvro teeth or 



prongs: name from the adjective, i. e. plant a Helens, therefore feminine.) Herbs, 

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



