352 COMPOSITiE. Bidens. 



merits connate at the base and decurrent on the petiole ; heads discoid, most- 

 ly on short pedicels ; scales of the exterior foliaceous involucre longer than 

 the head, lanceolate or oblanceolate, mostly obtuse, scarcely if at all ciliate ; 

 acheiiia narrowly cuneiform, glabrous, with retrorsely ciliate-hispid margins, 

 9_4.((;omnionlv 3-) avvned. — Muhl. in IVilld. ! spec. 3. p. 1718 {S^-herb. .') ; 

 Pursk, I. c. ; Ell. sk. 2. p. 430 ; Hook. ! I. c. ; DC. ! prodr. 5. p. 594. B. 

 cernua, Darlingt. ! jl. Cest. ed. I. p. 92. B. tripartita, Bigel. jl. Bost. ed. 

 2. p. 294. B. petiolata, Nutt. ! in jour. acad. Philad.l.p.Qd ; Darlingt.! 

 fi. Cest. ed. 2. p. 486. 



Swampy grounds, and margins of ponds, Canada and throughout the 

 Northern Slates! to Ohio! Kentucky! Missouri! and the western part of 

 Georgia. July-Sept. — (T) Stem 10-24 inches high, branched. Leaves 

 very smooth, thin and membranaceous when young, mostly conspicuously 

 acuminate at each end, frequently all undivided. Exterior involucre varia- 

 ble in size, sometimes 1-1^ inch long; the inner membranaceous, brown 

 with a yellowish scarious margin. Flowers greenish-yellow ; the rays gen- 

 erally, if not always wanting. — De Candolle has mistaken Hooker's mean- 

 ing, who, in stating that the leaves are sometimes ternate, does not mean ter- 

 nately verticillate. This species is introduced into Dr. Short's Catalogue of 

 Kentucky plants under the name of Bidens comosa. Hooker, but we are not 

 aware that Sir Wm. Hooker, or any other author, has ])ubiished a species 

 with this name. In the account of Drummond's Collections in the United 

 States, however, a 'Bidens comafa, Linn.'' is enumerated; but as Linnaeus 

 has no such species, we suppose B. connata, Muhl. to be intended. 



3. B. cernua (Linn.): glabrous, or often hairy towards the summit; 

 leaves undivided, lanceolate, unequally serrate, the upper ones slightly con- 

 nate ; heads (discoid or radiate) nodding ; exterior involucre longer than the 

 head ; achenia obovate-cuneiform, 4-awned, the margin retrorsely ciliate-his- 

 pid. — Linn. I spec. 2. p. 832 (var. discoidea) ; Engl. hot. t. 1114; Schkuhr, 

 handb. t. 235 ; Koch, fl. Germ- Sf Helv. p. 356 ; ^Hook. fl. Bor.-Am. 1. p. 

 314; DC. .' prodr. 5. p. 59o. B. minima, Linn, spiec. {ed.2)2. p. \.\Qb ; 

 Fl. Dan. I. 312. Coreopsis Bidens, Linn. spec. 2. p. 908. (var. radiata.) 



/?. elata : upper part of the (stout) stem and branches somewhat hirsute 

 with short white hairs ; leaves oblong-lanceolaie, unequally and incisely ser- 

 rate; rays inconspicuous. — B. chrysanthemoides. Hook.! Jl. Bor.-Am. 1. p. 

 314 (excl. syn.), S^' hot. Beechey, p. 148. ' B. quadriaristata, /3. dentata, 

 Nutt. in trans. Amcr. j)hil. soc. I. c. p. 368. 



Swamps and ditches, Canada and Saskatchawan, Hooker, to Pennsylva- 

 nia, Pwrs/?. Maine and Massachusetts, Mr. Oakes ! Western part of the 

 Stale of New York, Dr. Sartwell! (i. Oregon at Fort Vancouver, and 

 Straits of Da P'uca, Douglas, Dr. Scolder! Nuttall. (California, Beechey ?) 

 — (i) This species is said to be common in Canada, but in the United States 

 it is probably only to be found along the northern borders. The following 

 species approaches its radiate forms too closely ; but in B. cernua, the leaves 

 are more irregularly serrate, scarcely connate, and the outer involucre nearly 

 similar to the leaves, and much longer than the rays when these are present. 

 The Oregon plant is certainly much nearer this than the following species. 



4. B. chrysanthemoides (Michx.) : glabrous; stem erect or reclined at the 

 base ; leaves lanceolate; tapering to each end, more or less connate, regu- 

 larly and rather remotely serrate ; heads conspicuously radiate, erect or 

 nodding; scales of the foliaceous exterior involucre somewhat unequal, ob- 

 tuse, ciliate-serrulate towards the base, mostly shorter than the rays; the in- 

 terior oblong-ovate, membranaceous, partly colored; achenia cuneiform, with 

 retrorsely aculeolate-ciliate margins ; awns 2, 3, or 4. — Michx. ! Jl. 2. p. 

 136 ; Willd. ! spec. 3. p. 1717 C Pursh ! Jl. 2. p. 566. Coreopsis Bidens, 



