Stems to 50 cm × 0.1--0.7 mm. Leaves 6--10.5 cm; blade 0.3--0.5 mm, apex ± obtuse. Inflorescences: peduncles with 0--3[--4] coils, 0.5--16.5 × 0.5 mm. Flowers: pistils 4--8. Fruits 1.8--2 × 0.7--1.5 mm; gynophore 1.2--1.9 cm; beak terminal, slightly recurved, 0.6--1 mm. 2n = 16. Flowering spring--fall. Shallow waters of brackish streams, ditches, and lakes along ocean shore; 0--200 m; St. Pierre and Miquelon; B.C., N.B., Nfld. and Labr. (Nfld.), N.S., Ont., P.E.I., Que., Sask.; Ala., Alaska, Calif., Conn., Del., Fla., Ga., La., Maine, Md., Mass., Miss., N.H., N.J., N.Y., N.C., Oreg., R.I., S.C., Tex., Va., Wash.; coastal Mexico; West Indies; Bermuda; Central America; South America; Eurasia; Africa; Australia. No specimens have been seen from Washington, D. C., but the species is to be expected there.

Perennial submersed aquatic herb to 0.5 m tall Stem: slender, forking, rooting at lower nodes. Leaves: alternate, submersed, sheathing at the base, stalkless, 3 - 10.5 cm long, to 0.5 mm wide, linear with a more or less blunt tip, sometimes minutely toothed, one-veined. Inflorescence: a short, head-like spike of two flowers, on a terminal stalk. Stalk 0.5 mm - 1.65 cm long, to 0.5 mm wide, spirally twisting. Flowers: paired, tiny, lacking tepals. Stamens two, stalkless, opposite. Anthers two-chambered. Pistils four to eight. Fruit: a drupelet (a small, fleshy fruit with a stony center), long-stalked, 2 - 3 mm long, to 1.5 mm wide, obliquely egg-shaped, short-beaked, one-seeded.

Similar species: No information at this time.

Flowering: July

Habitat and ecology: Rare in the Chicago Region, typically being found in saline or brackish waters along the coasts and areas inland. Consequently, some botanists question its nativity in the Great Lakes area.

Occurence in the Chicago region: native

Etymology: Ruppia is named after the German botanist Heinrich Bernhard Ruppius (1689-1719). Maritima means "of or from the sea."

Author: The Morton Arboretum

. Stem to 8 dm; lvs 3-10 cm נ0.5 mm; fr 2-3 mm; 2n=14, 16, 20, 24, 28, 40. Interruptedly cosmopolitan; along both coasts of the U.S. in saline or brackish (rarely truly marine) water, and scattered inland in saline or brackish (rarely fresh) water. Highly variable, and by some authors divided into several apparently confluent spp. or vars.

Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.

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