This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol1", 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..
Low herbs with coated bulbs, very narrow grass-like leaves and slender 1-flowered scapes, the flower large, long, erect, subtended by a membranous spathe-like bract. Perianth salver-form with 6 oval or ovate spreading lobes united into a tube several times their length, the tube cylindric or slightly dilated at the summit. Stamens inserted on the throat of the perianth; filaments short; anthers linear, erect. Ovary 3-celled; style filiform; stigma slightly 3-lobed; ovules numerous, in 2 rows in each cavity of the ovary. Capsule depressed, globose or obovoid, 3-lobed, loculicidally 3-valved. Seeds numerous, horizontal, black. [In honor of Daniel Cooper, 1817?-1842, Curator, Botanical Society of London.]
C. Drummondii Herb. Bot. Reg. pl. 1835. 1836.
Bulb globose, about 1' in diameter. Leaves 6-12' long, 2"-3" wide, erect; scape slender, hollow, about as long as the leaves; spathe-like bract 1-2' long, 2-cleft above into acuminate lobes 4"-6" long; flower 3-5' high, white or pinkish; tube of the perianth very slender, about 1 1/2" in diameter, slightly expanded just below the limb; segments oblong, obtuse and cuspidate or acutish, nearly 1' long, 3"~4" wide, ovary sessile; capsule somewhat obovoid, about ¥ in diameter, deeply lobed.
On prairies, Kansas to Louisiana, Texas, Mexico and New Mexico. Prairie-lily. April-July.