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..
Prenanthes alba var. nana Bigel. Fl. Bost. Ed. 2, 286.
Gray, Man. Ed. 7, 871. 1908. Prenanthes serpentaria var. nana A. Gray, Syn. Fl.
1: Part 2, 434. 1884.
Glabrous throughout; stem simple, erect, 4'-16' high. Basal and lower leaves slender-petioled, 3-divided, or sometimes broadly hastate, the divisions variously lobed, toothed, or entire, usually sessile, occasionally stalked; upper leaves much smaller, entire, toothed, or lobed, sessile, or short-petioled; inflorescence thyrsoid, glomerate-spicate or racemose, rarely with 1 or 2 short ascending branches; involucre dark purple-brown or nearly black, glabrous, 4"-6" long, its inner bracts 6-8, slightly ciliate at the apex, about as long as the usually bright brownish pappus; outer bracts lanceolate to ovate-lanceolate.
Alpine summits of the Adirondacks and the mountains of New England; Nova Scotia to Labrador and Newfoundland. Aug.-Sept.
Prenanthes virgata Michx. Fl. Bor. Am. 2: 84. 1803.
Nabalus virgatus DC. Prodr. 7: 242. 1838.
Glabrous, somewhat glaucous; stem strict, mostly simple, 2°-4° high. Leaves lanceolate or oblong-lanceolate, the basal and lower ones sinuate-pin-natifid or pinnately parted, petioled, often 10' long, the lobes entire or dentate, distant; upper leaves all sessile, pinnately lobed, or the uppermost entire, very small and bract-like; heads very numerous, pendulous, about 2" broad, in a narrow, simple or branched, terminal thyrsus, often unilateral; involucre purplish, about \\" thick and 5" long, its principal bracts about 8, with several minute outer ones; flowers white or pinkish; pappus straw-color.
In moist sandy soil, New Jersey to Florida, near the coast. Called also De Witt's-snakeroot. Sept.-Oct.
Nabalus Boottii DC. Prodr. 7: 241. 1838. Prenanthes Boottii A. Gray, Syn. Fl. 1: Part 2, 435. 1884.
Glabrous below, commonly pubescent above; stem simple, 4'-12' high. Leaves thickish, the basal and lower ones ovate, hastate, or deltoid, petioled, mostly obtuse, entire, or denticulate, 1-2' "long, the upper ovate or oblong, usually entire, short-petioled or sessile, much smaller; heads several or numerous, 10-18-flowered, erect, spreading, or some of them pendulous, racemose or somewhat thyrsoid, 4"-5" broad; involucre cam-panulate-oblong, 21/2"-3" thick, 4"-7" long, dark purplish-green, its principal bracts 8-10, obtuse or obtusish, with several shorter outer ones; flowers whitish, odorous; pappus brownish.
Alpine summits of the mountains of northern New England and New York. July-Aug.