246 COMPOSITE, (composite family.) 



75. RUGEIilA, Shuttl. 



Heads many-flowered, the flowers all tubular and perfect. Scales of the cam- 

 panulate involucre lanceolate, equal, in a single row. Receptacle convex, naked. 

 Corolla 5-cleft. Style bulbous at the base, the long branches truncated at the 

 apex, and beset with rigid reflexed hairs. Achenia terete, striate. Pappus of 

 numerous rather rigid rough bristly hairs. — A perennial herb, with alternate 

 undivided leaves, and largo heads in a simple corymbose raceme. 



1. E. UUdicElulis, Shuttl. Minutely pubescent ; rhizoma creeping ; stem 

 simple, erect ; leaves ovate, acute at each end, denticulate ; the lowest ones large 

 (2' -4'), crowded, on long margined petioles, the others small, scattered, and 

 nearly sessile ; heads on long bracted peduncles. — Smoky Mountains, Tennes- 

 see, Rugel, Buckley. — Stem 1° high. 



76. ABWICA, L. 



Heads many-flowered, radiate ; the rays pistillate. Scales of the campanulate 

 involucre lanceolate, equal, in about two rows. Keceptacle flat, hairy. Achenia 

 terete, narrowed downward, somewhat ribbed. Pappus a single row of rough 

 bristly hairs. — Perennial herbs. Leaves opposite, undivided. Heads single or 

 corymbose. 



1 . A. nudicaulis, Ell. Hirsute ; radical leaves spreading, oval or ob- 

 ovate, obtuse, 3-5-ribbed, serrate or entire; the others (2-3 pairs), distant, 

 oblong, sessile ; heads corymbose, showy ; achenia smoothish. — Wet pine bar- 

 rens, Florida, and northward. April and May. — Stem l°-2° high, simple, or 

 with few opposite branches. 



Tribe V. CYNARE.S. Heads discoid ; the flowers all tubular ; the exterior 

 ones sometimes enlarged and ray-like : style thickened at the summit ; the stigmatic 

 lines extending to the summit of the branches, without appendages. 



77. CENTAUREA, L. Star-Thistle. 



Heads many-flowered ; the marginal flowers mostly large and sterile. Scales 



of the involucre imbricated. Receptacle bristly. Achenia compressed. Pappus 



of rough bristles in one or more rows, sometimes wanting. — Herbs. Leaves 

 alternate. Heads solitary. 



1. C. Calcitrapa, L. Stem difi'usely branched, hairy; leaves pinnately 

 lobed ; the lobes linear, toothed ; heads sessile ; involucre spiny ; pappus none. 

 — North Carolina. Naturalized. — Flowers purple. 



78. CIRSIUM, Tourn. Thistle. 



Heads many-flowered, discoid ; the flowers all similar and perfect. Scales of 

 the involucre imbricated in many rows, all but the innermost ones usually spine- 

 pointed. Receptacle bristly. Achenia oblong, compressed, smooth. Pappus of 

 numerous plumose hairs. — Herbs, with alternate sessile or decurrent mostly 

 pinnatifid and spiny leaves. Heads large, subglobose. Flowers purple or 

 whitish. 



