216 COMPOSITE. 



regularly and sharply rhombic-tetragonal; all truncate at the broad 

 summit and surrounded by a crenulate margin. Pappus of the outer 

 row of achenes reduced or wanting; of the others double, namely with 

 an outer set of elongated but unequal ciliate palese in several series, 

 and an uniserial and much shorter inner set. 



1. C. LANATUM (L.), DC. & Duby. A very rigid thistle-like yellow- 

 flowered annual, naturalized about South San Francisco, Biolelti. 



71. SILYBUM, Vaillant. Coarse and stout annual, with very large 

 sinuate-pinnatifid prickly leaves veined and blotched with white. Heads 

 large, at the ends of long pedunculiform branches. Involucre broadly 

 ovoid; bracts foliaceous, spinose along the margins, tapering into a 

 rigid prickle. Receptacle densely soft-bristly. Corollas all alike, red- 

 purple. Stamens monadelphous below. Achenes compressed and 

 smooth. Pappus multiserial, of narrow almost setiform barbellate 

 palese which are united slightly at base, and deciduous in a ring. 



1. S. MARIANUM (L.), Gaertn. One of the most common and trouble- 

 some of rank thistles, in all waste lands in California. 



72. CYNARA, Galen. Very stout perennials, with pinnatifid or 

 bipinnatifid sessile though not decurrent leaves; the lobes spinescent- 

 tipped. Heads very large; involucral bracts coriaceous. Receptacle 

 fleshy, fimbrillate. Achenes obovate compressed and somewhat 4-angled. 

 Pappus of many series of plumose bristles. 



1. C. SCOLTMUS, L. (ARTICHOKE). Stout and low, with very ample 

 hoary-tomentulose bipinnatifid leaves, the segments spine-tipped: iiivo- 

 lucral bracts ovate, obtuse or emarginate. Escaped from gardens near 

 Benicia, West Berkeley, Alameda, etc. 



73. CARDUUS, Pliny (THISTLE). Stout herbs, mostly biennial. 

 Leaves mostly sessile or decurrent, and with sharply spinose lobes or 

 teeth. Heads large, ovoid or subglobose; the pluriserial and imbricated 

 involucral bracts usually prickly-tipped. Receptacle densely villous- 

 setose. Flowers all alike, crimson, purple or white, the segments of the 

 corolla long and linear-filiform. Achenes obovate or oblong, compressed* 

 smooth, not striate; pappus a single series of long and barbellate or plu- 

 mose slender bristles concreted at base and deciduous in a ring, often 

 clavellate-dilated at the naked tip. 



* Bracts of involucre with dilated and sguarrose-spreading lips; 

 heads shorl-peduncled. 



1. C. fontinalis, Greene. Stout, 2 ft. high, the widely spreading 

 branches ending in middle-sized nodding heads: stem and upper sur- 

 face of leaves glandular-pubescent: bracts of the involucre herbaceous, 

 broad, squarrose-spreading or recurved, abruptly acute, with a short 



