MOXOPETALOUS EXOGENOUS PLANTS. 329 



of the involucre linear, acute; aclienia minutely glandu- 

 lar; stem twining. 



CONOCLINIUM, DC. 



Heads many-flowered ; scales of the inyolucre nearly 

 equal, imbricated in 2-3 rows ; receptacle conical, naked ; 

 corollab-ioot\iQ^] anthers included; achenia angled, smooth. 

 — Perennial herbs, with opposite petioled serrate leaves, and 

 heads of purple or blue flowers in a terminal corymb. 



C. CCELESTINUM, DC. Smoothisli ; leaves deltoid-ovate, 

 the lowest often cordate, acuminate, coarsely serrate; 

 heads 30-60-flowered ; floivers bluish-purple; stem 2° high. 



Tribe III. Aster oidese. Heads discoid or radiate, 

 the rays pistillate ; branches of the style, in the perfect 

 flower, flattened, linear or lanceolate, equally pubescent 

 above on the outside ; the conspicuous stigmatic lines ter- 

 minating where the exterior pubescence commences. 



SERICOCARPUS, ISTees. 



Heads 12-15-flowered ; the ray-fioivers about 5, white, 

 pistillate ; those of the disk tubular and perfect ; involucre 

 somewhat cylindrical or club-shaped ; the scales cartila- 

 ginous, whitish, closely imbricated in several rows, with 

 greenish and more or less spreading tips ; receptacle pitted, 

 toothed ; achenia short, obpyramidal, silky ; pappus simple, 

 composed of numerous capillary bristles. — Perennial herbs ; 

 leaves alternate ; heads crowded in a dense corymb ; disk- 

 flowers yellow. 



S. TORTiFOLius. Stem l°-2° high ; leaves V long, ob- 

 ovate, rarely serrate, vertical ; involucre top-shaped, scales 

 oblong and spreading slightly at the tips; pappus copious, 

 white. 



