[+][+] Flowers small, sessile (solitary or sometimes clustered) in the axils, with very small greenish petals (in n. 5) or mostly none; leaves mostly lanceolate or linear on the erect stems (1–3° high) and numerous branches; but prostrate or creeping sterile shoots often produced from the base, thickly beset with shorter obovate or spatulate leaves. (Our species glabrous, except n. 3.)
3. L. sphærocárpa, Ell. Minutely pubescent, especially the calyx, or nearly glabrous; leaves lanceolate or linear, acute, tapering at base, those of runners obovate with a wedge-shaped base and glandular-denticulate; bractlets minute, obsolete, or none; capsules globular or depressed (sometimes acute at base), not longer than the calyx-lobes (less than 2´´ long).—Water or wet swamps, E. Mass. to Fla. and La. Bark below often spongy-thickened.
4. L. polycárpa, Short & Peter. Leaves narrowly lanceolate, acute at both ends, those of the runners oblong-spatulate, acute, entire; bractlets linear-awl-shaped and conspicuous on the base of the 4-sided somewhat top-shaped capsule, which is longer than the calyx-lobes.—Wet places, E. Mass. and Conn. to Mich., Minn., E. Kan., and Ky.
5. L. lineàris, Walt. Slender, mostly low; leaves narrowly linear, those of the short runners obovate; minute petals usually present; bractlets minute at the base of the elongated top-shaped 4-sided capsule, which is 3´´ long and much longer than the calyx-lobes.—Bogs, pine barrens of N. J., and southward.
6. L. cylíndrica, Ell. Much branched; leaves oblong- or spatulate-lanceolate, much tapering at the base or even petioled; bractlets very minute at the base of the cylindrical capsule, which is 3´´ long, and several times exceeds the calyx-lobes.—Swamps, S. Ill. to Fla. and Tex.
[*][*] Leaves all opposite; stems creeping or floating.
7. L. palústris, Ell. (Water Purslane.) Smooth; leaves ovate or oval, tapering into a slender petiole; petals none, or small and reddish when the plant grows out of water; calyx-lobes very short; capsules oblong, 4-sided, not tapering at base, sessile in the axils (2´´ long).—Ditches, common. (Eu.)
8. L. arcuàta, Walt. Smooth, small and creeping; leaves oblanceolate, nearly sessile; flowers solitary, long-peduncled; petals yellow, exceeding the calyx (3´´ long); capsules oblong-club-shaped, somewhat curved ({1/3}´ long).—Swamps, Va. to Fla.
3. EPILÒBIUM, L. Willow-herb.
Calyx-tube not or scarcely prolonged beyond the ovary; the limb 4-cleft or -parted, deciduous. Petals 4. Stamens 8; anthers short. Capsule linear, many-seeded. Seeds with a tuft of long hairs at the end.—Mostly perennials, with nearly sessile leaves, and violet, purple, or white flowers; in summer. A large genus, many of its species of difficult limitation. The following provisional arrangement has been made by Prof. W. Trelease, mainly in accordance with Haussknecht's revision of the genus. (Name composed of ἐπί, upon, and λόβιον, a little pod.)