ASTERACEAE. 403 



Tribe 10. CYNAREAE. Thistle Tribe. 



Herbs with alternate prickly leaves and mostly large 

 heads. Involucral bracts imbricated, usually spinescent. 

 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. 



Filaments distinct. 



Pappus bristles plumose, deciduous in a ring. 



Pappus in 1 series. 65, Cirsium. 



Pappus in several series. 66. Cynara. 



Pappus bristles setose. 68. Centaurea. 



Filaments united into a tube. 67. Silybum. 



65. CIRSIUM 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- 

 fect and fertile or rarely dioecious, their corollas slender, 

 with deeply 5-cleft limb. Filaments pilose or rarely 

 glabrous. Achenes obovate or oblong, compressed or 

 obtusely 4-angled, smooth or ribbed. Pappus of several 

 series of slender plumose minutely serrulate or simple 

 bristles, connate at base. 



Heads sessile or short-pedunculate, leafy-bracted 



at base. 1. C. edule. 



Heads solitary on long peduncles, not leafy- 

 bracted at base. 

 Corolla-lobes longer than the throat, crimson. 2. C. calif or nicum. 

 Corolla-lobes equaling or shorter than the 



throat, white to pinkish. 3. C. occidentale. 



1. C. edule Nutt. Stout, 1-2 m. high, pubescent, leafy up to 

 the short panicle; leaves oblong or narrower, sinuate-pinnatifid, 

 weakly prickly; heads 3-4 cm. high, depressed-globose, few in a 

 terminal cluster, leafy-bracted at base; involucre arachnoid when 

 young; flowers deep purple, their segments shorter than the throat. 



Pasadena, McClatchie, 



