440 Cynareae 



glabrate above; basal leaves thin, 2-3 dm. high, elliptic-oblong, 

 acute at both ends, coarsely dentate, the teeth spreading, triangu- 

 lar, callous-tipped, the sinuses rounded and the larger denticulate, 

 lower leaves resembling the basal, the uppermost narrow lanceo- 

 late, entire or irregularly dentate; heads 1-2 cm. broad, less than 

 1 cm. high, 6-10 in a close cluster at the ends of the peduncles ; 

 rays none ; flowers all fertile. 



Wilson's trail at 2500 feet altitude, Davidson. 



4. S. Douglasii DC. Suffrutescent, usually about 1 m. high, 

 branching from the base, whitish-tomentose or becoming gla- 

 brate; lower leaves pinnately divided into about 5 narrowly 

 linear lobes, the uppermost entire, all with revolute margins; 

 heads rather few, corymbose, 10-15 mm. high; rays light yel- 

 low, 10 mm. long; achenes hoary with a short pubescence. 



Common on dry plains and foothills, mostly below 3000 feet altitude. 

 July-November. 



Tribe 10. CYNAREAE. THISTLE TRIBE. 



Herbs with alternate prickly leaves and mostly large 

 heads. Involucral bracts imbricated, usually spine'scent. 

 Receptacle bristly or hairy. Rays none. Corollas tubu- 

 lar, deeply and narrowly lobed. Anthers caudate at the 

 base and appendaged at the apex. Pappus bristly or 

 plumose, rarely paleaceous. 



Pappus bristles plumose, deciduous in a ring. 



Pappus in 1 series. 64. CARDUUS. 



Pappus in several series. 65. CYNARA; 



Pappus bristles setose. 66. CENTAUREA. 



64. CARDTJUS L. THISTLE. 



Erect, branching or simple, prickly herbs, with alter- 

 nate or basal sinuate dentate lobed or pinnatifid usu- 

 ally spiny leaves, and large many-flowered solitary or 

 clustered discoid heads of crimson purple or white 

 flowers. Involucre ovoid or globose, its bracts prickly- 

 tipped or unarmed, imbricated in many series. Recep- 

 tacle flat or convex, bristly. Flowers all tubular, per- 



