COMPOSITE FAMILT. 201 



49. POL"5?MNIA, LEAF-CUP. (These coarse and inelegant plajits arc 

 oddly dedicated to one of the Muses.) Fl. summer and autumn. 21. 



P. Canadensis, common in sliaded ravines N., is 3° - 5° high, clammy- 

 hairy, with thin leaves, the lower pinnatifid, the upper 3 - 5-lobed or angled, 

 and the few pale-yellow and broad rays of the small heads shorter than the 

 involucre. 



P. tJvedillia, in rich soil from New York to 111. and S., is roughish-hairy, 

 stout, 4° -10° high, with large ovate and angled or lobed leaves, the upp6r 

 ones sessile, and rays of the pretty large head 10-15, bright yellow, longer than 

 the involucre. 



50. SILPHITJM, ROSIN-PLANT. (Ancient Greek name of some very 

 different plant. ) Fl. summer and autumn, y. 



§ 1. Leaves alternate, large, most of them petiolcd. 



* The stout and rough flowering stems (3° - 6° high ) leafg up to the few large heads : 



scales of involucre ovate, with tapering and spreading rigid tips. 



S. lacini&tum, Rosin-Weed or Compass-Plant, of prairies, from Michi- 

 gan W. & S., so called because the rough-hairy deeply pinnatifid root-leaves (of 

 ovate outline) incline to present their edges N. & S. 



« • The slender smooth flowering stems (4° - 10° ^(17/1) leafy only near the base, 

 dividing above into a panicle of many smaller heads. 



S. terebinthiniceum, Praikie-Dock, so called from the appearance 

 of the large root-leaves, which are ovate or heart^oblong and 1° -2° long, besides 

 the slender petiole, the margins somewhat toothed : common W. 



S. compdsitum, from North Carolina S., is more .slender and smajler, with 

 round heart-shaped leaves either toothed or cut, or divided. 



§ 2. Leaves or many of them in whorls of 3 or i along the terete stems, rather small, 

 entire or coarsely toothed. 



S. trifoli&,tum, of S. & W., has the smooth stem 4° -6° high, lanceolate 

 ronghish leaves, and small heads. 

 S. Asteriscus, of dry soil S., is rough-hairy, with fewer and larger heads. 



§ 3. Leaves opposite and clasping or connate : items leafy' to the iot^ 

 S. integrif61iu.ni, in prairies from Michigan W. & S. ; ronghish, 2° -4° 



high, with lance-ovate partly heart-shaped and entire distinct leaves. 

 S. perfoliiltum, Cdp-Plant, of rich soil W. & S. : with very smooth 



square stems 4° - 9° high, around which the ovate coarsely toothed leaves are 



connate into cup which holds water from the rains. 



51. DAHLIA. (Named for a Swedish professor, Dahl, contemporary with 

 Linnaeus.) ^ Two or three Mexican species, of which the most familiar is 

 D. variabilis. Common Dahlia of the gardens, with pinnate loaves, ovate 



serrate leaflets, and large heads, much increased in size and altered, of all colors : 

 roots fascicled and tuberous (Lessons, p. 32, fig. 60). 



52. COKEOPSIS, TICKSEED. (Named from Greek word for biig, from 

 the shape of the akcnes.) Many wild species : several cult, for ornament: these 

 are the commonest. Fl. summer. (See Lessons, p. 106, 107, fig. 219, 220.) 



§ 1. Bays broad, coarsely 3 - H-toothed : outer involucre not longer ihan the inner ; 

 akenes orbicular or oval, incurved when mature. Chiefly cultifattd. 



* ® ® Diskflowers and lower part of the rays darJc-colored or brdum-purple : 

 akenes in these species vnngless and nearly naked at tup : leaves compound. 



C. tinet6ria, of Arkansas, &c., the commonest Coreopsis or Calliopsis 

 of all country gardens ; smooth, with lower leaves twice-piunately divided into 

 narrow leafiete, numerous heads, and lower half or sometimes almost the whole 

 of rays brown-purple : in one variety they are changed to tubes. 



