CICHOEIACEAE. 



383 



1. Urospermum picroides (L.) F. W. 

 Schmidt. UROSPERMUM. (Fig. 416.) Annual, 

 more or less hispid, simple or branched, 6'-18' 

 high. Basal and lower leaves spatulate or ob- 

 long, petioled, toothed or runcinate, 2'-4' long; 

 upper leaves lanceolate, sessile, clasping, mostly 

 sagittate, toothed or entire, smaller, acute or 

 acuminate; heads about 1A' broad, solitary at 

 the ends of hollow peduncles 3'-6' long; bracts 

 of the involucre lanceolate, acuminate, 8" 10" 

 long; achenes fusiform, curved, including the 

 subulate beak 8"-10" long; pappus bright 

 white. [Tragopogon picroides L.] 



Abundant in fields and on hillsides, eastern 

 part of St. David's Island, 1909. Naturalized. 

 Native of southern Europe. Flowers in spring. 



Lactuca sativa L., LETTUCE, European, is grown successfully as a garden 

 vegetable in several races; its flowering stems are 2-3 high, leafy, the obovate 

 or elliptic leaves obtuse and irregularly toothed, the small numerous yellow- 

 flowered heads borne in terminal panicles. 



Tragopogan porrifolius L., SALSIFY, OYSTER-PLANT, European, also grown 

 as a vegetable, is a tall herb, with long narrow leaves, and large heads of 

 purple flowers on thickened peduncles, the bracts of the involucre much longer 

 than the rays. 



Family 5. AMBROSIACEAE Reiehenb. 

 RAGWEED FAMILY. 



Herbs, monoecious, or sometimes dioecious, many of them weeds, rarely 

 shrubby, with alternate leaves, or the lower opposite, and small heads of 

 greenish or white flowers subtended by an involucre of few, separate or 

 united bracts, the pistillate heads sometimes larger and nut-like or bur- 

 like. Staminate and pistillate flowers in the same, or in separate heads. 

 Receptacle chaffy. Pistillate flowers with no corolla, or this reduced to 

 a short tube or ring; calyx adnate to the 1-celled ovary, its limb none, or a 

 mere border; style 2-cleft. Staminate flowers with a funnelform tubular 

 or obconic 4-5-lobed corolla; stamens mostly 5, separate, or their anthers 

 merely oonnivent, not truly syngenesious, with short inflexed appendages; 

 ovary rudimentary; summit of the style often hairy or penicillate. Eight 

 genera and about 60 species, mostly natives of America. 



Fruit large, bur-like ; leaves broad, lobed. 



Fruit small, tubercled ; leaves deeply lobed or pmnatifid. 



1. Xanthium. 



2, Ambrosia. 



