200 COMPOSITE. (composite family.) 
marked by its great smoothness, pale glaucous foliage, its copious 
rather large heads with triangular green tips to the otherwise white 
involucre, and the showy bright sky-blue rays. 
* * * Lower leaves all heart-shaped and petioled y the upper sessile or 
petioled: involucre imbricated much as in the last division , but the 
heads smaller , very numerous , racemose or panicled. 
Leaves entire or slightly serrate: heads middle-sized: rays bright-blue. 
10. A. aziircus, Lindl. (Rough Sky-blue Aster.) Stem 
rather rough, erect, racemose-compound at the summit, the branches 
slender and rigid ; leaves rough; the lower ovate-lanceolate or oblong , 
heart-shaped , on long often hairy petioles ; the others lanceolate or lin- 
ear , sessile , on the branches awl-shaped; involucre inversely conical. 
— Copses and prairies, Ohio to Wisconsin. — A handsome species; 
the involucre much as in No. 9, but slightly pubescent; the rays 
bright blue. 
11. A. Slidrtii, Boott. (Short’s Aster.) Stem slender, 
spreading, nearly smooth, bearing very numerous heads in racemose 
panicles; leaves smooth above , minutely pubescent underneath , lanceo¬ 
late or ovate-lanceolate y elongated , tapering gradually to a sharp point, 
all but the uppermost more or less heart-shaped at the base and on naked 
petioles ; involucre bell-shaped.—Cliffs and banks, from Ohio south¬ 
ward and westward. —A beautiful species, 2°-4° high; the leaves 
& -5 7 long. 
13. A. undulatus, L. (Variable Aster.) Pale or some¬ 
what hoary with close pubescence; stem spreading, bearing numer¬ 
ous heads in racemose panicles; leaves ovate or ovate-lanceolate , with 
wavy or slightly toothed margins , roughish above , downy underneath , 
the lowest heart-shaped on margined petioles, the others abruptly con¬ 
tracted into short broadly winged petioles which are dilated and clasping 
at the base, or directly sessile by a heart-shaped base; involucre obo- 
void. (A. diversifblius, Michx .) — Dry copses, common. 
^ Leaves conspicuously serrate: heads small: rays pale. 
13. A. cordifolius, L. (Heart-leaved Aster.) Stem much 
branched above, the spreading or diverging branches bearing very nu¬ 
merous panicled heads; lower leaves all heart-shaped, on slender and 
mostly naked ciliate petioles ; scales of the inversely conical involucre 
all oppressed and lipped with short green points , obtuse or acutish. — 
Woodlands, very common. Varies with the stem and leaves either 
smooth, roughish, or sometimes hairy underneath. Heads in great 
prolusion, but quite small. Rays pale blue. 
• ^ Willd. (Arrow-leaved Aster.) Stem 
rigid, erect, with ascending branches bearing numerous racemose heads; 
leaves ovate-lanceolate, pointed; the lower heart-shaped at the base, 
on margined petioles; the upper lanceolate or linear, pointed at both 
ends; scales of the oblong involucre linear , tapering into awl-shaped 
