This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol2", 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..
Erect, very slender, simple or branched, 6'-18' high, glabrous or nearly so below, finely pubescent above. Stem-leaves filiform-linear, entire, crowded, 6"-15" long; basal leaves tufted, oblanceolate or spatulate, petioled, about 1' long; flowers in loose spike-like racemes, yellow, diurnal, 3"-4" broad; calyx-lobes short, reflexed, the tube about 1" long, rather shorter than the ovary; stigma-lobes very short; capsule obovoid, sessile or very nearly so, puberulent, sharply 4-sided but not winged, 2 '-3" long.
In dry soil, Illinois to Kansas, south to Georgia, Louisiana and Texas. May-July.
Oenothera fruttcosa var. humifusa Allen, Bull. Torr.
1894. Kneiffia Alleni Small, Bull. Torr. Club 23: 177. 1896.
Low, perennial, finely appressed-pubescent, stems decumbent, at length diffusely branched, 3'-2° long, wiry and zigzag. Leaves oblanceolate to lanceolate, 1/2'-1 1/4' long, usually obtuse, undulate, sessile or short-petioled; flowers yellow, about 3/4'-1' broad; racemes 1'-2' long, usually interrupted; calyx villous, its tube 2"-3" long, striate, its segments linear-oblong, as long as the tube; petals orbicular-obovate, notched at the apex; capsules club-shaped, 3"-4" long, winged, shorter than the pedicels; seeds obovoid, to oblong, i" long, minutely pitted in rows.
In sand, eastern Long Island. Probably a decumbent race of K. linearis. June-Aug.
3. Kneiffia longipedicellÓta Small. Long-stemmed Sundrops. Fie. 3051.
Kneiffia longipedicellata Small, Bull. Torr. Club 23:
Perennial, slender, more or less puberulent; stems erect or assurgent, 1°-2 1/2° tall, red, simple or sparingly branched above. Basal leaves spatulate or obovate-spatulate, 1 1/2' - 3' long; stem-leaves few, linear-lanceolate 1'-2 1/2' long, obtuse or acutish, entire, sometimes undulate, short-petioled; flowers yellow, 1'-2' broad; racemes 1'-4' long; calyx hirsute, its tube slender, 5"-7" long, its segments nearly linear, longer than the tube, the tips free in the bud; petals obovate, emarginate; capsules narrowly obovoid, the bodies about 5" long, their angles with stout pubescent wings, their faces ridged, the pubescent pedicel longer than the body; seeds irregular, less than i" long, minutely papillose.
Moist soil, Connecticut to West Virginia and Florida. May-Aug.