(113) 



1. C. Americanus Gray. Involucre ovoid; 

 bracts appressed, imbricate, with loose, sca- 

 rious tij^s; flowers ocliroleucous. — 0. Ma- 

 rin County. Summer. 



2. C. EDULis Gray. Bracts of the involucre 

 not appressed, not rigid, but loose, tapering 

 from a narrow base gradually into a short flac- 

 cid spine; corolla lobes filiform, with a thick- 

 ened tip; flowers purple or whitish. — 0. 

 Common. Summer. 



3. C. Hallii Gray. Bracts of the involucre 

 not appressed, not rigid, but loose, tapering 

 from a narrow base gradually into a flaccid, 

 short spine; corolla lobes linear, flat; flowers 

 rose-color or whitish. — 0. Marin County, 

 Summer. 



4. C. occmENTALis Gray. Bracts of the in- 

 volucre with short coriaceous base and squar- 

 rose, subulate tips; heads solitary, terminal, 

 very large; flowers crimson. Common. Sum- 

 mer. 



5. C. FONTiNALis Greene. Bracts of the in- 

 volucre herbaceous, broad, reflexed, with a 

 short spinose tip; heads nodding; flow^ers 

 whitish. — Crystal Springs; very local. Sum- 

 mer. 



6. C. QUERCETORUM Gray. Bracts of the in- 

 volucre appressed, coriaceous, only the outer 

 mucronate, the inner unarmed; all plane without 



