Aster COMPOSITAE 929 



Upper stem leaves not cordate-clasping; bracts glabrous or with ciliate margins 

 except nos. 1 and 2. 



Peduncles and branches of the inflorescence more or less glandular 



1. A. macrophyllus. 



Peduncles and branches of the inflorescence not glandular. 

 Rays white. 



Bracts linear, all acute or acuminate, mostly less than 0.6 mm wide; 



peduncles usually short and many-bracted 



6a. A. sagittifolius var. urophyllus. 



Bracts various (the lower mostly ovate, obtuse or acute, the middle 



ones oblong, obtuse, and the inner ones linear and obtuse or acute) , 



more than 0.6 mm wide; peduncles generally naked. 



Leaves slightly scabrous above, glabrate beneath; involucres mostly 



6-7 mm long; lower bracts ovate, obtuse or subacute, the middle 



ones mostly narrow-oblong, generally 1-1.3 mm wide, obtuse, the 



inner ones linear, obtuse or acute. (See excluded species no. 627, 



p. 1097) A. divaricatus. 



Leaves very scabrous above, rather densely hispidulous beneath; in- 

 volucres mostly 7-8 mm long; bracts generally obtuse and wider 

 than the preceding, the middle ones generally 1.4-1.8 mm wide. . . . 



2. A . furcatus. 



Rays blue or violet. 



Plants usually not leafy below, internodes of the stem long; upper 

 leaves linear and subulate-pointed; leaves of branches linear and 

 closely appressed, subulate-pointed; lower cauline leaves subcordate 

 or narrowed at the base, thick, their margins entire or shallow- 

 serrate, scabrous above and beneath; inflorescence paniculate, the 

 branches widely spreading; heads usually secund and terminating 



long scaly peduncles; bracts with short-acute, green tips 



3. A . azureus. 



Plants not agreeing with the preceding description. 



Leaves entire (sometimes some leaves with a part of the margin ser- 

 rate), thick, firm, ovate-lanceolate or lanceolate, glabrous or 

 slightly scabrous above (rarely very rough), more or less short- 

 pubescent beneath, sometimes glabrous; petioles not margined at 



the base; bracts linear, short-acute 4. A. Shortii. 



Leaves more or less sharply serrate, thin or firm. 

 Bracts short-acute, mostly with colored tips; leaves thin; lowest 

 stem leaves of an ovate to broadly ovate type, generally 

 strongly cordate and sharply serrate, the petioles usually not 



margined 5. A. cordifolius. 



Bracts long taper-pointed, rarely some of them with colored tips; 

 leaves firm; lower stem leaves usually not deeply cordate, 

 mostly of an ovate-oblong type, usually less serrate and teeth 

 not so long, generally all or at least the upper ones with mar- 

 gined petioles. 



Stems of plants essentially glabrous or pubescent in lines 



6. A. sagittifolius. 



Stems of plants usually densely short-pubescent 



7. A. Drummondii. 



Upper stem leaves and those of the branches more or less sessile and cordate- 

 clasping; lower stem leaves usually with margined, clasping petioles; 



bracts pubescent, rarely glabrous S. A. undulatus. 



A. Basal leaves not both cordate and petiolate; lower stem leaves relatively narrow, 

 cordate and sessile, more or less narrowed at the base and sessile or nar- 



