SYNGENESIA.— NECESSARIA. 313 



* * * Leaves alternate. 



4. C. gladiata : stem smooth, dichotomous above: 

 leaves narrow-lanceolate, very entire, thick, atten 

 uated into a petiole ; seed obovate, winged ; the 

 wings serrulate ; pappus 2-bristled. 

 HAB. Sphagnous swamps. Sept. $. Stem 2 ft. 

 high; rays 8, 3-tooth., yell. 

 j. C.aspera: leaves lanceolate-linear, rough ; upper 

 ones alternate, inferior opposite ; stem 1 -flowered, 

 HAB. Maryland. 



503. ACTINOMERIS. Composite. 



A? squarrosa: stem erect, winged, pubescent and 

 paniculate above ; leaves lanceolate, serrate, sca- 

 brous ; calyx spreading, loose ; receptacle subglo- 

 bose, at length squarrose. 



HAB. Swamps. Aug. U. Stem 3— 4 ft. high: 

 leav. altern.; rays long, -wh. or yell. 



NECESSARIA. 



504. SILPH1UM. Composite. 



5. ternatum : stem terete, smooth ; leaves verticil- 

 late by three;?, petiolate, lanceolate, unequally 

 subdentate, somewhat scabrous, ciliate at the base ; 

 upper ones scattered and sessile ; panicle dicho- 

 tomous ; calyx ciliate. 



HAB. Mountain meadows. July. U. Stem A — 

 (}ft. high ; Jl. corymb., loose, yell. 

 2. S. trifoliatum ; stem G-angled, smooth ; leaves ver~ 

 ticillate by threes, ovate-lanceolate, unequally 

 toothed and serrate, scabrous ; upper ones ses- 

 sile ; panicle trichotomous. 



HAB. River swamps. Aug. U • Stem 5 — Oft- 

 high ; lower leav. subovate ; rays 14, yell. 

 ). S. perfoliatum : stem quadrangular, smooth ; leaves 

 opposite, connate, ovate, serrate. 



HAB. Mountains. Aug. U. Steffi 6 ft. high. 

 petiol. decurrent ; rays 24, yell. 



