COMPOSITACEAE (COMPOSITE FAMILY) 221 



Anthers without tails at base. Style branches somewhat club-shaped, 

 obtuse. Pappus bristles capillary, in i series, scabrous to almost plumose. 



A. Akenes s-angled, without intermediate ridges or lines; involucre bracts nearly 

 veinless. E. — (Honor of Mithridates Eupator, king of Pontus, who first used one 

 of these in medicine.) Eupatorium occidentale (boneset) 



AA. Akenes lo-ribbed or -striate; involucre bracts striate-veined. — ■ (Gk. koleos — 

 a sheath, anthos = a flower; probably referring to the involucre.) 



Coleosanthus (thoroughwort) 



ASTEREAE (Aster Tribe). — Leaves mostly alternate. Heads radiate 

 or rayless, all alike (except staminate and pistillate on separate plants in 

 Baccharis) ; receptacle naked. Ray flowers pistillate or rarely neutral. 

 Corolla of disk flowers nearly always yellow, regular, tubular, 4-5-lobed; 

 style branches flat, appendaged. Anthers not tailed at base. Pappus none * 

 or various, in most species of capillary bristles. 



A. Rays none or very inconspicuous. 

 B. Herbs though sometimes woody at base; hairy or glabrous, not usually sticky; 

 heads all alike. 

 C. Pappus of 2-8 rigid awns; involucre glabrous and shining but very gummy. 



GRINDELIA (p. 223) 

 CC. Pappus of scabrous capillary bristles; involucre often glandular but then not 

 glabrous. 

 D. Involucre bracts in 2-6 vertical rows. — (Gk. chrysos = gold, thamnos = a 

 shrub; shrubby plants with yellow flowers.) Chrysothamnus (rabbit brush) 

 DD. Involucre bracts not in vertical rows. 

 E. Leaves all entire. 

 F. Heads only i on a stem. 

 G. Involucre glandular; plant 15-30 cm. high, white-tomentose. (See T.) 



Aplopappus 



GG. Involucre hairy, not glandular; plant 5-15 cm. high, white-puberulent 



to glabrous. (See QQ.) Erigeron (fleabane) 



FF. Heads more than i on a stem. 



H. Plant white-tomentose; involucre glandular. (See T.) Aplopappus 



HH. Plant not tomentose; involucre rarely glandular. 



I. Involucre bracts recurved at tip. (See Y.) Aster (aster) 



II. Involucre bracts appressed or erect, not recurved. 



J. Involucre bracts in 1-3 whorls, herbaceous; annual or biennial. (See 

 QQ.) Erigeron (fleabane) 



JJ. Involucre bracts in 3 or more whorls, scarious, often with green tips, 

 thin or firm; perennial. 

 K. Leaves oblong; plant viscid-pubescent, 1.5-3 dm. high. (See Q.) 



Chrysopsis (golden aster) 

 KE. Leaves ovate-lanceolate; plant glabrous or nearly so, not viscid, 6-9 

 dm. high. (See Y.) Aster (aster) 



EE. Leaves or at least the lower ones not entire. 

 L. Teeth of the leaves spinulose-tipped. (See T.) Aplopappus 



LL. Teeth of the leaves not spinulose-tipped. (See Y.) Aster (aster) 



LLL. Leaves or nearly all of them entire. 

 M. Involucre bracts recurved at tip. (See QQ.) Erigeron (fleabane) 



MM. Involucre bracts erect or appressed at tip, not recurved. (See Y.) 



Aster (aster) 



