404 COMPOSITAE LACTUCA 



SONCHUS 



L. SCARIOLA L. Sp. ed. 3, 1119. Biennial: glabrous throughout or hir- 

 sute at the base ; green and glaucous : stem stout, 2-7 feet high, leafy, 

 usually paniculately branched: leaves lanceolate to oblong, with spinu- 

 lose-denticulate margins, sometimes sinuate, toothed or pinnatifid, ses- 

 sile or auriculate-clasping, midrib below beset with weak prickles: heads 

 small, 6-12 flowered, very numerous, in an open panicle: corollas pale 

 yellow: achenes obovate-oblong, several-nerved, marginal, about as 

 long as the filiform beak. Becoming common in fields and waste 

 places. Introduced from Europe. 



L. SATiVA. The common Lettuce is common along the railroad in the 

 southern part of Oregon but is hardly naturalized. 



L. Canadensis L. Sp. ii, 796. Biennial or annual : glabrous and glau- 

 cescent : stem strict, 4-12 feet high, very leafy up to the elongated nar- 

 row panicle : leaves mostly sinuate-pinnatifid, 6-12 inches long, with mar- 

 gins entire or sparingly dentate, and midrib naked or rarely some sparse 

 bristles, most of the cauline partly clasping by a sagittate or auriculate 

 base : involucre half-inch or less high, 12-20-flowered : flowers yellow : 

 achenes blackish, obscurely scabrous-rugulose, lightly 1-nerved on the 

 middle of each face, broadly oval, with distinct thin margins, rather 

 longer than the beak: pappus white. Moist woods, Oregon and Wash- 

 ington to the Eastern States. 



L. sagittifolia Ell. Bot. S. C. & Ga. ii, 253. Glabrous; 3-6 feet high, 

 leafy nearly to the usually loosely paniculate inflorescence: leaves oblong 

 to lanceolate, 3-10 inches long, acute or acuminate, entire or denticulate, 

 the lower sometimes pinnatifid, whitish beneath, midrib naked: involucre 

 5-7 lines high : flowers pale yellow or purplish : achenes oval, thin-mar- 

 gined, longer than the beak. Open ground. Idaho to the Eastern States. 



§ 3 Lactucastrum Gray Syn. Fl. i, pt. 2, 443. Root perennial. 

 Involucre well imbricated. Achenes lanceolate-oblong, flat, not 

 margined, tapering into a beak not longer than the breadth of 

 the body. 



L. pulchella DC. Prodr. vii, 134. Very glabrous : stems 1-5 feet high, 

 leafy up to the open corymbiform panicle: leaves from linear-lanceo- 

 late to narrowly oblong, entire or runcinate-dentate, or some lower 

 ones pinnatifid: cauline sessile but not auriculate at base: branches of 

 the loose panicle scaly: involucre 8 lines high, 12-15-f lowered, its outer 

 bracts ovate-lanceolate: flowers bright blue or violet-purple: achenes 

 barely 2 lines long, striate-nerved, the tip of the short beak soft and 

 usually whitish. Alluvial ground, Oregon to Brit. Columbia, Hudson 

 Bay and Michigan. 



§ 3 MuLGEDiuM Gray 1. c. Biennial or perennial herbs with 

 usually bluish flowers. Achenes thickish, oblong, with some 

 strong ribs and nerves: contracted at summit into a short stout 

 beak, or into a mere neck under the dilated apex. 



L. spicata Hitchc. L. leucophaea Gray . Stem usually stout, 3-12 feet 

 high, leafy up to the panicle : leaves 3-12 inches long by 2-6 broad, sinu- 

 ately or runcinately pinnatifid, coarsely and irregularly or doubly dentate; 

 upper cauline sessile by a mostly narrow but auriculate or partly clasping 

 base : heads in a pyramidal crowded panicle : involucre oblong, 5 lines 

 high: flowers bluish: achenes narowed at summit to a short' but manifest 

 neck. Moist ground, Oregon to Brit. Columbia and the E. States. 



