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..
Oenothera rhombipetala Nutt.; T. & G. Fl. N. A. I: 493. 1840.
Erect, simple or rarely branched, finely and densely appressed pubescent, 2°-4° high. Leaves linear-lanceolate, sessile and rounded at the base or the lower narrowed into petioles, acuminate at the apex, remotely denticulate, 2-4' long; flowers in terminal, leafy-bracted spikes, yellow, nocturnal, 1'-2' broad, calyx-lobes linear, reflexed, canescent, shorter than the very slender tube; petals rhombic-obovate; capsule columnar, curved upward, pubescent, 6"-8" long, about 1" thick; seeds obovoid, tuberculate at the top.
On prairies, Minnesota to Indiana, Nebraska and Texas. June-July.
9. ÁNOGRA Spach, Ann. Sci. Nat. (II.) 4: 164. 1835.
Low caulescent herbs. Stems often clothed with a papery bark. Leaves alternate, entire or usually pinnatifid. Buds drooping; flowers perfect, white or pink, usually axillary, diurnal. Calyx-tube elongated, gradually enlarged upward, calyx-segments narrow, finally reflexed, the acute tips free or united in the bud. Stamens 8, equal in length; filaments filiform; anthers linear. Ovary elongated, 4-celled; united styles filiform; stigma deeply 4-cleft; ovules numerous, in 1 row, ascending. Capsules elongated, spreading or ascending, 4-angled, loculicidal. Seeds ascending, in 1 row, terete. [Anagram of Onagra.]
About 10 species, chiefly in southern North America. Type species: Anogra Douglasiana Spach.
Tips of the calyx-segments not free in the bud.
Tips of the calyx-segments free in the bud.
Throat of the calyx-tube villous within.
Throat of the calyx-tube glabrous within.
Capsules narrowly ascending; leaves linear, entire or nearly so.
Capsules widely spreading; leaves lanceolate, dentate.
Oenothera pinnatifida Nutt. Gen. 1: 245. 1818.
Annual or biennial, diffusely branched at the base; branches decumbent or ascending, more or less hirsutely pubescent or puberu-lent, whitish and often shreddy, 4'-12' long. Basal and lower leaves petioled, the upper sessile, oblanceolate or lanceolate in outline, deeply pinnatifid or the lowest repand-dentate (rarely entire), 1'-4' long; flowers axillary, diurnal, l 1/2 - 3' broad, white, becoming rose-color; petals obcordate or emar-ginate; calyx-segments lanceolate, not free in the bud, acuminate, hirsute, finally re-flexed, the throat naked; capsules linear, 1'-1 1/2' long, about 1" thick, hirsute or pu-berulent; seeds finely pitted.
Prairies, North Dakota to Nebraska, New Mexico and Sonora. April-June.