368 DESCRIPTIONS OF NEW SPECIES 



Helianthus Missouriensis; (Schweinitz, MSS.,) -extremely scabrous; leaves 

 atenuate, radical spathulate, serrate, cauline oblong obtuse, uppermost linear, 

 acute; stem dichotomous, the branches diverging, one-flowered; sepals ovate, 

 minutely ciliate, closely imbricate; stigma lanceolate, hirsute, golden yellow. 



Hab. Plains of Missoui-i. Closely allied to H. paucijlorus. 



Division IV. — BiDENTiDEiE. [Lessing. Becand.) 



BIDENS. (Linn.) 



BiDENs quadriaristata. /?. * dentata; leaves remotely dentate, serrate, outer 

 involucrum about five-leaved, longer than the oval rays. 

 Hab. Wappatoo Island, at the outlet of the Wahlamet, Oregon. 



Bidens Californica. 



Hab. St. Diego and St. Barbara, Upper California; common, O- Also in Chili. Rays nearly 

 white, inclining to yellow, often wanting. 



§. Campylotheca. — (Genus Campylotheca, Cass. Decand.) Achenium linear, 

 sometimes curved or contorted, linear and compressed ; arvns trvo, small, or 

 wanting. 



Bidens *mutica; very smooth and herbaceous; leaves ternately or pinnately 

 divided; leaflets ovate-lanceolate, acuminate, serrate; panicle trichotomous; ex- 

 terior involucrum a little shorter than the inner; rays about five, twice as long 



as the disk; achenium straight, sparingly pilose, without awns. 



Hab. Ouau, Sandwich Islands. Less than a foot high, the lower leaves quinate, the uppermost 

 nearly simple. Flowers yellow, rather small; the inner and outer involucrum each about five- 

 leaved. Disk dark brown; tube of the florets nearly the length of the border. Branches of the 

 stigma terminated by short conic appendages. The achenium smooth, or with a few scattered hairs, 

 transversely striated, sometimes with a single awn, but mostly without any; branchlets of the panicle 

 about three-flowered, the capituli on long pedicels. 



Bidens "^gracilis; smooth and herbaceous; leaves ternately or pinnately di- 

 vided, leaflets lanceolate, acuminate, serrate; panicle slender, trichotomous; 

 exterior involucrum a little shorter than the inner; rays about five, scarcely 

 longer than the disk; achenium somewhat curved, with two short awns, having 

 a few retrorse bristles towards the extremity. 



