. 1208 CARDUACEAE 
Leaves rough, thin : chief petioles not winged : inflores- 
i cence broad-panicled. 
Bracts linear-acute or subulate. 
Pubescence downy or absent. 
Tall: chief leaves ovate-lanceolate, thin : sinus open: 
heads compound-racemed. 
Low: chief leaves faleate-lanceolate: sinus obsoles- 
cent: heads thyrsoid. 
Cinereous or canescent pubescence present. 
Plants tomentulose, very rough above: sinus broad. 
Leaves coraaie Oyate. crenate in:the middle, thin- 
nish. 
Leaves prolonged. sharp-toothed, thick. 
Plants but lightly pubescent. 
Leaves oval-acute, thinnish : sinus deep and nar- 
row. 
Leaves long-triangular, thick : sinus little developed. 
B. Leaves rough on both sides, of a spongy, crumbling texture. 
Chief leaves moderately broad : rays blue. 
Chief leaves oblong-lanceolate, shallow-serrate, short : 
: I. bracteate, È 
Chief leaves elliptic-lanceolate, crenate: pedicels con- 
spicuous, nude. 
Chief leaves grass-like : branches very diffusely decompound. 
Radical leaf-blades chiefly with truncate bases. 
Radical leaf-blades chiefly with taper bases. 
No dilated-clasping petioles. Biotian and Heterophyllous Asters, Nos. 1-28. 
Some petioles dilated, leaf-like and clasping around the stem, tapering nar- 
rowly toward the blade. Diversifolial Asters. : 
Polymorphous leaf-forms present, no one type strongly predominant. 
Leaves not delicate, pubescent, rough when dry : inflorescence broad, 
divergently compound. 
Leaves delicate, firm, rough, with little hair: inflorescence narrowly 
racemose. 
Some predominant leaf-form present. 
Predominant leaves broad, not greatly elongated. 
Predominant leaves tomentulose beneath, ovate-oblong, thick and 
rough, diminutive. 
Predominant leaves sparse-pubescent beneath, petioled, short-cor- 
date, thinnish. 
Predominant leaves elongated. 
Predominant leaves triangular-attenuate. 
Slender plants : leaves chiefly petioled and clasping. 
Robust when fully developed : leaves chiefly sessile. 
Leaf-bases narrow : axils usually foliose. 
Leaf-bases broad : leaves very rough. 
Predominant leaves not triangular. 
Predominant leaves linear-oblong with straight sides. — 
Leaves soft, thinnish: many long strap-like petioles : inflores- 
cence racemose. 
i Leaves very rough, thick, usually sessile: inflorescence decom- 
pound. 
Plant not glandular: leaves strap-shaped or thong-like. 
Plant somewhat glandular: leaves grass-like, narrower. 
Predominant leaves ovate-oblong to elongated-lanceolate. 
Leaves firm, crisp: stem bearing stalked glands: inflorescence 
irregular, narrow, often clavate. 
Leaves thinnish: plant without glands: inflorescence some- 
what thyrsoid. 
Basal and lower cauline leaves with relatively broad blades, ovate-cordate, 
long-petioled, ete. Biotian, Heterophyllous and Diversifolial Asters, Nos. 1-40. 
Basal and lower cauline leaves with relatively narrow blades, with more or less 
contracted petiole-like bases but not cordate: upper cauline leaves with 
sessile or clasping blades. 
Blades of the cauline leaves more or less clasping by auriculate-cordate bases. 
Amplexicaul Asters, Nos. 41-63. 
a. Chief bracts rigid, closely "n (unless at the tip). 
Stem glabrous: leaves firm, sleek or subsucculent. 
Involucre campanulate. 
Leaves glabrous except the edges. : 
Bracts oblong-linear with broad rhomboid or deltoid green tips. 
Cauline leaf-blades oblong or oval-lanceolate : inflorescence 
tending to the racemose panicle. 
Cauline leaf-blades linear or elongated-lanceolate : inflores- 
cence tending to the corymbose panicle. 
Bracts linear, their green tips narrowly lanceolate. 
Cauline leaves linear or narrow-lanceolate. 
Cauline leaves very narrowly linear’: heads very small. 
Leaves glabrous above, often with minute hair beneath. 
Leaves entire, short, oblong-elliptical, remote. 
Leaves often coarsely toothed, ponu linear in type. 
Involucre turbinate or clavate: leaf-blades scarcely clasping. 
Stem "ars leaves pubescent with short hair: involucre campanulate or 
turbinate. 
18. 
29. 
30. 
39. 
40. 
41. 
42. 
43. 
44. 
45. 
46. 
47. 
A. cordifolius. 
. A. sagittifolius. 
A. plumarius. 
. A. hirtellus. 
2. A. Drummondii. 
. A. Texanus. 
. A. trigonicus. 
A. azureus. 
. A. capillaceus. 
. A. vernalis. 
3. A. poaceus. 
A. undulatus. 
A. Protcus. 
. A. asperifolius. 
: y aylvestris. 
. A. truellius. 
A. corrigiatus. 
. A. triangularis. 
. A. linguiformis. 
. A. loriformis. 
. A. Mohrii. 
A. claviger. 
A. gracilescens. 
A. laevis. 
A. concinnus. 
A. purpuratus. 
A. attenuatus. 
A. ursinus. 
A. falcidens. 
A. turbinellus. 
