1. J. decúrrens, DC. _Stem erect_ (1--2° high), branching, _winged_ by the decurrent lanceolate leaves; _calyx-lobes 4_, as long as the petals; _capsule oblong-club-shaped, wing-angled_; seeds in several rows in each cell.--Wet places, Va. to Fla., west to S. Ill., Ark., and La. 2. J. rèpens, L. _Stem creeping, or floating and rooting_; leaves oblong, _tapering into a slender petiole_; flowers large, long-peduncled; _calyx-lobes and obovate petals 5_; pod woody, cylindrical, with a tapering base; seeds quadrate, in 1 row in each cell, adherent to the spongy endocarp.--In water, Ill. and Ky. to E. Kan., Ark., and Tex. 2. LUDWÍGIA, L. FALSE LOOSESTRIFE. Calyx-tube not at all prolonged beyond the ovary; the lobes 4, usually persistent. Petals 4, often small or wanting. Stamens 4. Capsule short or cylindrical, many-seeded. Seeds minute, naked.--Perennial herbs, with axillary (rarely capitate) flowers, through summer and autumn. (Named for _C. G. Ludwig_, Professor of Botany at Leipsic, contemporary with Linnæus.) [*] _Leaves all alternate, sessile or nearly so._ [+] _Flowers peduncled in the upper axils, with conspicuous yellow petals (4--8´´ long), equalling the ovate or lanceolate foliaceous lobes of the calyx._ 1. L. alternifòlia, L. (SEED-BOX.) _Smooth_ or nearly so, branched (3° high); _leaves lanceolate to linear-lanceolate, acute or pointed at both ends_; capsules cubical, rounded at base, wing-angled.--Swamps, E. Mass. to Fla., west to Mich., E. Kan., and La. 2. L. hirtélla, Raf. _Hairy_ all over; stems nearly simple (1--2° high); _leaves oblong, or the upper lanceolate, blunt at both ends_; capsules nearly as in the last, but scarcely wing-angled.--Moist pine barrens, N. J. to Fla. and Tex. [+][+] _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.