This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol3", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Lactuca saligna L. Sp. Pl. 796. 1753.
Biennial, light green; stem slender, smooth or nearly so, 2° high or more, the very slender branches erect-ascending. Leaves glabrous, linear to oblong, 6' long or less, runcinate-pinnatifid with pointed divergent lobes, or entire, sagittate at the base, the midvein sometimes spinulose; panicles narrow; heads about 3" broad, few-flowered; involucre subcylindric; outer bracts much shorter than the inner; achenes oblong, about one-half as long as the filiform beak; pappus white.
Waste and cultivated grounds, Ohio. Naturalized from Europe. July-Aug.
Biennial, glabrous throughout, leafy up to inflorescence, paniculately branched, 2°-5° high. Leaves oblong to ovate-oblong, acute or acutish, 2.'-4 long, auriculate-clasping, spinulose-denticulate, sinuate-lobed, or pinnatifid with spinulose segments; heads 3"-5" broad, numerous in an open panicle, their peduncles bracteolate; involucre cylindric or ovoid-cylindric, glabrous, 8"-9' high, its bracts successively shorter and broader, the lower ones ovate; rays yellow; achenes oval to obovate, flat, about the length of their filiform beak; pappus white.
Plains and banks, Iowa, Minnesota and South Dakota to Kansas and Texas. July-Sept.
Lactuca hirsuta Muhl. Cat. 69. 1813. Lactuca sanguinea Bigel. Fl. Bost. Ed. 2, 287. 1824. Lactuca elongata var. sanguinea T. & G. Fl. N. A. 2: 496. 1843.
Stem 1°-6° high, naked and paniculately branched above, usually hirsute, at least below. Leaves, or most of them, sinuate-pinnatifid, pubescent on both sides, or on the midrib beneath, those of the stem mostly sessile or auriculate-clasping, 3'-7' long, the uppermost sometimes lanceolate and entire, the basal petioled; heads numerous, 2"-3" broad; involucre glabrous, 5"-9' high; outer bracts shorter than the inner; rays reddish-yellow or paler; achenes oblong-oval, flat, about the length of the beak; pappus white.
In dry soil, Quebec to Ontario, Minnesota, Alabama and Texas. Stem, peduncles and involucre often red or purple. July-Sept.
L. Steelei Britton, Man. 899. 1901.
Stem and branches hirsute. Leaves obovate to oval, the larger about 8' long and 4' wide, sessile, irregularly dentate, not lobed, hispid on the veins beneath, short-acuminate; involucre about 6" high; rays not seen; achenes oval, 3-ribbed, about \\" long, the filiform beak slightly shorter; pappus bright white.
Near Washington, D. C, and, apparently, in Delaware. July-Aug.