COMPOSIT.*:. (COMI'OSITE lAMILV.) 255 



* * Pappus tvliite ; leaves entire, obscnreli/ veined, Jinner and smaller. 



2. S. SOlidagineus, Nces. Smooth, slender; leaves linear, rigiil, obtuse, 

 ■with rou^li niar>:;ius, tai)ering to the base; heads narrow (3" long), in close 

 clusters, fL'\v-Ht)\\ rrcd. — Thickets, S. New Eng. to Tenn., and southward. July. 



3. S. tortifolius, Nees. Hoary-pubescent; leaves obovate or oljlong- 

 spatulatc, short (i - 1' long), vertical, both sides alike; heads rather lo(jsely 

 corynibed, obovoid (4-5" long). — Pine woods, Va. and southward. Aug. 



25. ASTER, L. Starwokt. Aster. 



Heads many-flowered, radiate; the ray-flowers in a single series, fertile. 

 Scales of the involucre more or less imbricated, usually with herbaceous or 

 leaf-like tips. Receptacle flat, alveolate. Achenes more or le.ss flattened ; 

 papi)us simple, of ca])illary bristles (double in §§ 4 and 5). — I'erennial iierbs 

 (annual only in §§ 7 and 8), with corymbed, panicled, or racemo.se heads; 

 flowering in autumn. Kays wliite, purple, or blue; the disk yellow, often 

 changiiig to purple. (Name aar-np, a star, from the radiate heads of flowers.) 



Conspectus of Gi'oups. 



Annuals, with copious fine soft pappus 53, 54 



Pappus double 4G-48 



Scales closely imbricated, not gi'een-tii>ped, often scarious-edged .... 40-52 

 Scales closely imbricated, scarcely at all herbaceous ; leaves cordate, sen-ate . 2, 3 



Scales neaj-ly eqiuil, rigid, more or less foliaceous; pappus-bristles rigid, some 



thickened at top 1 



Scales with herbaceous tips or the outer wholly foliaceous. Asteu proper. 

 Pajipus rigid; stem-leaves sessile, none cordate or clasping ; heads few, large . 4-S 



Leaves silvery-silky both sides, sessile, entire 14, 15 



Lower leaves more or less cordate, petiolate 17-24 



Leaves entire, lower not cordate, cauline sessile with cordate-clasiiing base . IG 



Involucre (and branchlets) viscid or glandular ; leaves uot cordate, mostly entire, 



the cauline all sessile or clasping 9-13 



Lower leaves all acute at base ; not glandular nor viscid nor silky-canescent. 

 Smooth and glabrous, usually glaucous ; scales coriaceous at base ; leaves firm, 



usually entire 25-30 



Hoary-pubescent or hirsute ; scales scjuarrose ; stem-leaves small, linear, entire 31, 32 

 Scales closely imbricated, not coriaceous at base; branches divaricate; heads 



many, small 83-35 



Remaining species ; branches erect or ascending. 

 Stem-leaves auric.ulate-clasping or with winged-petiole-like base; involucre lax 42-45 

 Stem-leaves sessile, but rarely cordate or auriculate at base .... 30-41 



§ 1. HELlASTRUM, Pappus simple, coarse and rigid, the sti-otiger bristles 

 somewhat clavate ; scales rigid, more or less foliaceous, nearly equal. 



1. A. palud6stlS, Ait. Stems 1° high; glabrous or nearly so; heads 

 V higli, rather few, racemose or spicate; outer scales lax, foliaceous; rays 

 purple; leaves linear, entire. — Kan. to Tex., thence to Car. and Ga. 



§ 2. BIOTIA. Involucre obovoid-bell-shaped ; the scales regularly imbricated 

 in several rows, apjiressed, nearly destitute of herbaceous tips; rays 6-18 

 {ivhite or nearly so) ; achenes slender ; pappus slightly rigid, simple ; lower 

 leaves large, heart-shaped, petioled, coarsely serrate ; heads in open corymbs. 



2. A. COrymbbsus, Ait. Stejn slender, somewhRt zigzag; leaves thin, 

 smoothish, coarsely and unequally serrate with sharp spreading teeth, taper-pointed , 



