1208 



CARDUACEAE 



Leaves rough, thin : chief petioles not winged : inflores- 

 cence broad-panicled. 18. A, cordifolius. 

 Bracts linear-acute or subulate. 

 Pubescence downy or absent. 



Tall : chief leaves ovate-lanceolate, thin : sinus open : 



heads compound-racemed. 19. A. sagittifolius. 



Low : chief leaves falcate-lanceolate : sinus obsoles- 

 cent : heads thyrsoid. 20. A. plumarius. 

 Cinereous or canescent pubescence present. 



Plants tomentulose, very rough above : sinus broad. 

 Leaves cordate-ovate, crenate in.the middle, thin- 



nish. 21. A. Mrtdlus. 



Leaves prolonged, sharp-toothed, thick. 22. A. Drummondii. 



Plants but lightly pubescent. 



Leaves oval-acute, thinnish : sinus deep and nar- 

 row. 23. A. Texanus. 

 Leaves long-triangular, thick : sinus little developed. 24. A. trigonicus. 

 B. Leaves rough on both sides, of a spongy, crumbling texture. 

 Chief leaves moderately broad : rays blue. 



Chief leaves oblong-lanceolate, shallow-serrate, short : 



pedicels bracteate. 25. A. azureus. 



Chief leaves elliptic-lanceolate, crenate: pedicels con- 

 spicuous, nude. 26. A. capillacfiis. 

 Chief leaves grass-like : branches very diffusely decompound. 



Radical leaf-blades chiefly with truncate bases. 27. A. vernal ie. 



Radical leaf-blades chiefly with taper bases. 28. A . poaceus. 



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. Diversijolial Asters. 



Polymorphous leaf-forms present, no one type stronglv predominant. 

 Leaves not delicate, pubescent, rough when dry : inflorescence br< 



divergently compound, 

 lelicate. ' 



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. 



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, etc. Biotian, Heterophyllous and Diverrifolial 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 appressed (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, prolonged, linear in type. 

 Involucre turbinate or clavate : leaf-blades scarcely clasping. 

 Stem and leaves pubescent with short hair : involucre campanulate or 

 turbinate. 



29. A. undulatus. 



30. A. Proteus. 



31. A. aspeiifolius. 



32. A. fylvestris. 



SB. A. truellius. 



34. A. corrigiatus. 



35. A. triaiigutaris. 



36. A. linguiformis. 



37. A. loriformis. 



38. A. Mohrii. 



39. A. claviger. 



40. A. gracilescens. 



41. A. laens. 



42. A. concinnus. 



43 A.purpuratus. 



44. A. attenuatus. 



45. A. ursinus. 



46. A. falcidens. 



47. A. turbinellus. 



