1318 CICHOEIACEAE 



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. 1. S. asper. 



Stem-leaves with acute auricles: achenes striate and transverse-wrinkled. 2. S. oleraceus. 



1. Sonchus ^sper (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-lanceo- 

 late: 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 and the civilized world. 

 Naturalized from Europe. Spring to fall. 



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



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



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



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, S mm. broad or smaller: achenes 



2.5-3 mm. long, striate, finely trans\'erse-wrinkled. 



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

 the civilized world. Naturalized from Europe. Spring to fall. 



8. TARAXACUM Hall. 

 Perennial low acaulescent herbs, with a bitter sap. Leaves basal, often numerous: 

 blades sinuate-toothed to runcinate-pinnatifid, or rarely entire, the segments entire or 

 toothed. Heads yellow, usually solitary at the ends of hollow elongated sometimes 

 tufted peduncles. Involucres double; inner of 1 series of erect nearly equal slightly 

 united bracts; outer of several series of shorter spreading or reflesed bracts. Recep- 

 tacle flattish, naked. Eays yellow, often numerous, truncate and toothed at the apex. 

 Anthers sagittate at the base. Stigmas slender, rather obtuse. Achenes oblong or 

 somewhat fusiform, 4-5-angled, 5-10-ribbed, often tuberculate or spinulose at least 

 below the slender beak. Pappus of numerous white hair-like bristles, persi,stent. 

 Dandelion. 



1. _ Taraxacum Taraxacum (L.) Karst. Foliage glabrous or nearly so. Leaves 

 spreading; blades spatulate to oblauceolate or oblong, irregularly dentate to runcinate- 

 pinnatifid, 3-30 cm. long, more or less pubescent especially when young: scapes solitary 

 or tufted, erect or ascending, 1-2 dm. long, or much longer after flowering: heads 

 with 150-200 golden-yellow flowers: involucres 1.5-2 cm. high: bracts acute, linear to 

 linear-oblanceolate ; inner much longer than the outer: achenes about 3 mm. long, 

 rather fusiform; body spinulose near the top; beak about i as long as the body. [T. 

 officinale Weber.] 



On open grounds and waste places, in nearly all parts of the civilized world. Through- 

 out the year. 



9. TRAGOPOGON L- 



Biennial or perennial caulescent herbs, with slender tap-roots and rather succu- 

 lent tissues. Leaf-blades narrow, long-attenuate, clasping or sheathing at the base. 

 Heads peduncled, relatively large, exjianding in the early morning, usually closing by 



