CICHOKIACEAE 



1317 



7. Lactuca pulch611a (Pursh) DC. Perennial, glabrous, more or less glaucous. 

 Stems erect, 3-7 dm. tall, corymbosely paniculate above : leaves 5-20 cm. long, numer- 

 ous ; blades linear to lanceolate, entire, toothed or pinnatifid, acute or obtuse, those of basal 

 and lower stem-leaves sometimes with winged petioles, those of upper stem-leaves sessile 

 and partly clasping : peduncles often copiously scaly : involucres 16-20 mm. long ; inner 

 bracts linear-lanceolate, acute or obtusish : ligules blue or violet : achenes black, the body 

 rather elliptic, ribbed, 4 mm. long ; beak shorter than the body. 



In moist places, Ontario to the Northwest Territory and British Columbia, south to the Indian Ter- 

 ritory, New Mexico and California. Spring to fall. 



8. Lactuca villosa Jacq. Annual or biennial, rather slender. Stems erect, 1-2 m. 

 tall, paniculately branched above, glabrous : leaf-blades elliptic, oval or oblong-lanceolate, 

 8-20 cm. long, acuminate, irregularly dentate, narrowed into winged petioles or nearly 

 sessile: peduncles commonly with few scales : involucres 10-13 mm. high; bracts linear- 

 lanceolate to lanceolate, often purple : ligules blue : achenes elliptic, 4 mm. long, with 

 thick margins and 3 ribs on each face, beakless, not narrowed into a slender neck. 



On banks or in thickets, New York to Illinois, south to Florida and Kentucky. Summer and fall. 



9. Lactuca Floridana (L. ) Gaertn. Annual or biennial, stout or stoutish. Stems 

 1-3 m. tall, paniculately branched above, often mottled : leaf-blades thin, commonly ample, 

 36-45 cm. long, lyrate-pinnatifid ; segments irregularly toothed, the terminal one usually 

 triangular : involucres 10-12 mm. high ; bracts linear-lanceolate to linear, deep green or 

 purplish : ligules blue : achenes curved, 6-7 mm. long, each narrowed into a neck. 



On hillsides and open grounds, New York to Nebraska, Florida and Louisiana. Summer and fall. 



10. Lactuca spicata (Lam.) A. S. Hitchcock. Biennial, glabrous. Stems erect, 1- 

 3.5 m. tall, paniculately branched above : leaf-blades 1-4.5 dm. long, merely toothed or 

 sinuately or uncinately pinnatifid ; segments coarsely and irregularly dentate : peduncles 

 often sparingly scaly : involucres 9-11 mm. high ; bracts lanceolate to linear-lanceolate, 

 pale or scarious-margined : ligules white, bluish or yellowish : achenes 5 mm. long, each 

 with a wing-like margin and thinly ribbed faces, narrowed into a very short neck. [Z. 

 leucophaea A. Gray. ] 



In dry or moist soil, Newfoundland to Manitoba, North Carolina, Tennessee and Iowa. Summer 

 and fall. The variety with merely toothed leaf-blades, is L. spicata integrifolia (A. Gray) Britton. 



7. SONCHUS L. 



Annual or perennial caulescent weedy herbs, with succulent tissues. Leaves alternate ; 

 blades entire, toothed or pinnatifid, often clasping, the edges and midnerve beneath often 

 prickly. Heads yellow, peduncled, disposed in corymbose panicles. Involucres various, 

 glabrous or pubescent : bracts herbaceous or membranous, in several rows of gradually 

 differing lengths. Receptacle flat, naked. Ligules yellow, often numerous, truncate and 

 toothed at the apex. Anthers sagittate at the base. Stigmas slender. Achenes more or 

 less flattened, linear to oval, truncate, beakless, 10-20-ribbed, the ribs often undulate or 

 toothed. Pappus conspicuous, of numerous white hair-like bristles, deciduous. Sow 

 THISTLE. 



Stem-leaves with rounded auricles : achenes ribbed, or the base smooth. 

 Stem-leaves with acute auricles : achenes striate and transverse-wrinkled. 



1. S. asper. 



2. S. oleraceus. 



1. Sonchus asper (L. ) All. Annual, nearly glabrous. Stem erect, 2-15 dm. tall, 

 simple or somewhat branched : leaf-blades tender, spatulate to oblong, 5-25 cm. long, 

 with copiously spine-tipped teeth, the upper ones clasping by rounded bases : peduncles 

 often glabrous : involucres about 1 cm. high ; bracts linear to linear-lanceolate : heads pale 

 yellow, 2.5 cm. broad or smaller : achenes about 2 mm. long, margined, 3-ribbed on each 

 side. 



In waste places, throughout most parts of North America andj the civilized world. Naturalized 

 from Europe. Spring to fall. 



2. Sonchus oleraceua L. Annual, nearly glabrous. Stems erect, 1-18 dm. tall, 

 more or less widely branched : leaf-blades various, those of basal or lower stem-leave, 

 lyrately-pinnatifid, with a triangular terminal segment ; those of upper leaves shorters 

 runcinately or lyrately-pinnatifid, the teeth tipped with soft spine-like teeth, the basal lobes 

 acute : peduncles often glandular-hirsute : involucres about 1 cm. high ; bracts lanceolate- 

 subulate to lanceolate: heads pale yellow, 3 mm. broad or smaller: achenes 2.5-3 mm. 

 long, striate, finely trans verse- wrinkled. 



In waste places and fields, throughout North America, except the extreme north, and the civilized 

 world. Naturalized from Europe. Spring to fall. 



