ir4 STNGENESIA. FRtSTRANEl. 



florets minutely 5-toothed, viscid. Seed short and obca- 

 nic, shorter than the chaffy calicle. Pappus about 5 or 

 6-leaved, awned.f Receptacle hemispherical, naked. Hab, 

 On high gravelly hills near Fort Mandan, Missouri. Flow- 

 ering in June and July. 



Of this genus, which does not appear to have any natu- 

 ral affinity with Hymenopappus, there is a second species^ 

 indigenous to Buenos Ayres. 



Order III.— POLYGAMIA FRUSTRANEA. 



(Discal florets bisexual; rays neutral, sterile.) 



586. ^LEPTOPODA.i: 



Calix simple, many-parted. Rays 20 or more, 

 semitiifid, broader at the sumuiit. Receptacle 

 naked, hemispherical. Pappus paleaceous, 8 to 

 10-leaved, awnless. 



Herbaceous; stem 1-flowcred, peduncle very long^ 

 leaves alternate, decurrent, very entire and smooth; flower 

 entirely yellow. 



L. Helemum. Galardia fmbriata? Mich. Flor. 2. p. 142. 



Ons. Perennial. Very smooth. Stem attenuated, and 

 grooved, about 2 feet long. Peduncle 12 inches, a little 

 enlarged under the calix. Leaves few, linear-lanceolate, 

 eutir^ and very smooth, decurrent, lower ones 6 to 8^ 

 inches long, attenuated downwards, slightly punctate and 

 thickish, only 3 or 4 lines broad, the uppermost sessile, 

 linea% and not more than 2 iuches long. Calix short and. 

 simple like that of Ileleniiim, segments foliaceous and 



f The number of paleaceous leaflets crowning the seeds of 

 many syngenesious genera, will often be found to consiitule 

 more essential generic distinctions, than many others which are 

 constantly adduced; in some genera these leaflets are about 5, in 

 a smaller number 6 to 8, or 8 to 10, and in others 12 to 15. Not- 

 withstanding their minuteness, they appear to hold the relative 

 importance of the divisions of the calix, in which number is 

 indisputably important. 



i. So called ia aUugion to the ^ongated peduncle. 



