208 DICOTYLEDONOUS PLANTS.' 



HAB. In water. Can, and N. Y. July, Aug. If. Stem V. 

 feet long, simple or with very small and slender branches arising 

 from the axils of.thte upper leaves. Lower leaves very multifid. 

 capillary, as in Rartunculus aquatilis ; upper ones about an inch 

 and a" half long, broadly lanceolate, attenuated at each exlrewi- 

 ty, deeply serrated. Flowers solitary, at the extremity^of the 

 stem, rather large, yellow. Rays much longer tjian'the involu- 

 cre. This^peciea was first discovered in a pond 1 near Schenec- 

 tady, N. Y. It has since been found in Canada, by Mr. Goldie. 

 and. more recently in the western part of N. Y. by Drs: Asa 

 Gray and William Aikin. WaJUgr Mary gold.. 



44. POLYMNIA. Linn. 



Involucre- double ; the outer one 4 5-leaved ; the inner 10- 

 leaved ; leafets concave. Receptacle chaffy. Pappus none. 



Syngencsia. Necessaria. 



1. P. caiiadcnsls Linn. : viscid and yilloua ; leaves denticulate, acu- 

 minate ; lower ones pinnatifid, upper 3-lobed or entire. 



HAB. Shady hills. Can. to Car. June, 5uly. 'If. Stem N 2 4 

 feet high. Leaves thin, slightly scabrous. Flowers in a loose 

 terminal panicle, yellow. 



2. P. uecdalia, Linn. : leaves opposite, "3-lobed, acute, decurrdnt into 

 a petiole ; lobes angled and sinuate ; rays elongated. 



HAB. Mountains. Penn. to Car. July Sept. If. Stem 3 5 

 . feet high, terete. Leaves opposite or alternate. Flowers in a 

 loose terminal panicle ; rays about 10, 3-toothed, yellow. 



45. SILPHIUM. Linn. 



Involucre leafy, squarrose. Rcccptach\\\aSy. Seeds com- 

 pressed, obcordate-marginate, 2-toothed. 



'Syngen esia . Necessaria . 



1. S. perfoliatum Linn.: stem 4-angled, smooth; leaves opposite, 

 connate, ovate, serrate. 



HAB. Mountains. Penn. to Car. Aug. 11. StemQ feet high, 

 angled, smooth. Peduncles terminal and from the axils of the 

 highest leaves ; rays 24, yellow. 



a. & trtfoliatum Linn, .-'stem 6-angled, smooth; leaves verticillate 

 by threes, ovate-lanceolate, une^hally toothed and serrate, scabrous on 

 the upper surface ;\ipper orie.s sessile, panicle trichotomous. & terni- 

 folium Mich. .*..' 



HAB. Mountains. N. S. Torr. S. to Car. Sttyt.. Oct. If. 

 . Stem 46 fe.et high, mostly purple. Floors in a terminal' co- 

 rymb ; rays about 14, long, bright yellow. 



3. S. tenvatum Reiz: stem terete, smooth; leaves. vertLcillate by 

 thres, petiolate, lanceolate," slightly toothed, ciliate at base, somewhat 

 scabrous; upper ones scattered, sessile ; panicle dichotomous; in 

 volucre ciliate*. 



