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..
Leaves thick with many parallel veins, the petioles long, sheathing, arising from a horizontal rootstock. Stem erect, 1-leaved, with several sheathing bract-like leaves at the base. Flowers blue, ephemeral, numerous, spiked, the spike (or spadix) peduncled and subtended by a thin bract-like spathe. Perianth 2-lipped, the upper lip of 3 ovate lobes, the middle lobe longest, the lower lip of 3 linear-oblong spreading lobes. Stamens 6, borne at unequal distances upon the perianth-tube, 3 of them opposite the lower lip, the others opposite the upper lip; anthers oblong, subversatile, introrse. Ovary 3-celled, 2 of the cells abortive and empty. Fruit a i-seeded utricle, enclosed in the thickened tuberculate-ribbed base of the perianth. [In honor of Giulio Pontedera, 1688-1757, professor of botany in Padua.]
Seven or eight species, natives of America. The following is the type of the genus.
Pontederia cordata L. Sp. PI. 288. 1753-
Pontederia lancifolia Muhl. Cat. 34. 1813.
Pontederia cordata var. angustifolia Torr. Fl. N. U. S.
1: 343. 1824. Pontederia cordata lancifolia Morong, Mem. Torr. Club
5: 105. 1894.
Stem rather stout, 1°-4° tall. Leaves ovate to lanceolate, cordate-sagittate, truncate or narrowed at the base, 2'-10' long, 1/2'-6' wide, the apex and basal lobes obtuse; basal lobes often with long narrow stipule-like appendages on the sheathing petiole; spadix and inflorescence glandular-pubescent; perianth about 4" long, it and the filaments, anthers and style bright blue, its tube curved, slightly longer than the lobes, middle lobe of the upper lip with 2 yellow spots at the base within; ovary oblong, tapering into the slender style; stigmas minutely 3-6-toothed.
Borders of ponds and streams, Nova Scotia to Minnesota, south to Florida and Texas. After flowering the lobes and upper part of the perianth-tube wither above, while the persistent base hardens around the fruit. The flowers are trimorphous. Includes several races, differing in width of leaves. June-Oct.