CYNAROCEPHALJSJ. 215 



several times their own length, and having 1 or 2 spinules at base; outer- 

 most bearing a few small palmate prickles; innermost only scarious- 

 tipped: corollas yellow: pappus double; outer of short and squamellate, 

 inner of large bristles. — Very common in Napa Valley, less frequent in 

 other parts of middle California. 



3. 0. Memtensis, L. Erect, 2 — 4 ft. high, cinereous-pubescent, or 

 when young slightly woolly: radical leaves lyrate-pinnatifid; cauline 

 lanceolate, mostly entire, narrowly decurrent: principal bracts of invo- 

 lucre with a slender spine of about their own length which is pectinate- 

 spinulose at base; innermost with spinescent tips : flowers yellow: pap- 

 pus of very unequal rather rigid bristlesor squamellate.— A very common 

 field and wayside weed. 



* * Bracts of involucre unarmed, merely fringed; marginal 

 corollas much larger than the others. 



4. C. Oiancs, L. Slender, 1 — 2 ft. high, not prickly, whitened, at 

 least when young, with floccose wool: leaves linear, entire, or the lower 

 toothed or pinnatifid: heads naked, on slender peduncles: involucral 

 bracts narrow, fringed with short scarious teeth: marginal flowers 

 asexual, much enlarged, irregularly and somewhat palmately cleft and 

 ray -like, blue or pinkish or white: pappus of unequal bristles about 

 equalling the achene. — Escaped from gardens to waysides; also occasional 

 in grain fields; everywhere admired for the beauty of its flowers, and 

 called Cornflower, Bluebottle, etc. 



69. CNICUS, Vaillant. Annual with sinuate-pinnatifid leaves thin- 

 nish and reticulate-veiny, only weakly prickly. Heads enclosed within 

 large leafy accessory bracts. Proper bracts of the involucre thin-coria- 

 ceous, in few ranks, many or all of them abruptly tipped with an 

 aristiform or spinescent and pectinate-prickly appendage. Eeceptacle 

 densely setose with long and soft bristles. Achenes terete, strongly 

 many-striate, the corneous margin at summit 10-toothed. Pappus 

 double; each set consisting or 10 aristiform bristles; the outer set longer 

 and naked, the inner short and flmbriolate. 



1. C. benedicttjs, L. A less rigidly thistle-like annual, with pale 

 yellow flowers in large leafy-involucrate heads; occurring rarely as a 

 ballast waif at San Francisco. 



70. CENTROPHTLLUM, Necker. Annual or biennial. Leaves am- 

 plexicaul, reticulate-veiny, rigid, pinnatifid, and spinescent. Outer 

 bracts of involucre foliaceous, with few . spinescent lobes; the inner 

 firmer, appressed, not cleft, but with a dilated and spinescent tip. 

 Eeceptacle densely setose-paleaceous. Flowers yellow. Achenes obpyr- 

 amidal; those of the marginal row more plump, somewhat convex and 

 gibbous on one side, more angular on the other; those of the disk more 



