Herbs, annual or perennial, not stranded by low tide. Leaves submersed and emersed; submersed leaves sessile, blade linear; emersed leaves petiolate, blade hastate to sagittate. Inflorescences of 1--15 whorls, floating or emersed; bracts distinct. Flowers: pistillate with ring of sterile stamens; petals without purple spot at base. Flowering mid summer--fall. Mud flats of lakes and rivers; 5--2000 m; Ala., Ark., Calif., Colo., Del., Ga., Ill., Ind., Iowa, Kans., Ky., La., Mich., Minn., Miss., Mo., Nebr., N.Mex., N.C., Ohio, Okla., S.C., S.Dak., Tenn., Tex., Va., W.Va., Wis. ; Mexico (Chihuahua, Coahuila, Sinaloa).
Annual or perennial aquatic herb to 1 m tall Leaves: submersed and emersed, with linear submersed leaves to 0.5 cm wide and arrowhead-shaped emersed leaves 40 cm - 0.6 m long. Inflorescence: floating or emersed, singly stalked along a central axis (raceme), or with loosely branched stalks (panicle), arising from a stalk 10 cm - 1.5 m long, with one to fifteen whorls of flowers. Flowers: either male or bisexual, with male flowers on upper part of inflorescence and bisexual flowers near base, 2 - 5 cm wide. Male flowers have spreading sepals and cylindric filaments that are longer than the anthers and lack scales. Bisexual flowers have erect sepals enclosing the flower and a ring of sterile stamens. Fruit: a cluster of achenes 1.2 - 2.1 cm in diameter. Each achene is 2 - 4.3 mm long, 0.7 - 1.5 mm wide, narrow and inversely egg-shaped, with a horizontal beak 0.4 - 0.8 mm long. Bracts: lance-shaped to elliptic, not fused, delicate.
Similar species: Sagittaria latifolia, Sagittaria brevirostra, Sagittaria cuneata, and Sagittaria montevidensis ssp. calycina all have emersed arrowhead-shaped leaves and filaments lacking scales. Sagittaria latifolia has nearly all emersed leaves that are highly variable (linear to arrowhead-shaped) and achenes with beaks spreading horizontally. Sagittaria brevirostra also has mostly emersed leaves, but they are nearly all arrowhead-shaped. The edges of S. brevirostra achenes are minutely shallow-toothed and the beaks are ascending. Sagittaria cuneata has submersed ribbon-like leaves, floating lance- to arrowhead-shaped leaves, emersed arrowhead-shaped leaves, and achenes with short, erect beaks. Additionally, each of the above species has separate male and female flowers and reflexed or spreading sepals.
Flowering: June to September
Habitat and ecology: A rare species growing in marshes, shallow water, and along pond margins and shorelines.
Etymology: Sagittaria comes from the Latin word sagitta, meaning arrow, referring to the leaf shape. Calycina means calyx-like.
Author: The Morton Arboretum
Annual, erect, or lax in deep-water forms; petioles elongate, terete, very spongy, typically with emersed or floating, hastate or sagittate blade 4-60 cm, the terminal lobe linear to deltoid-orbicular, the basal lobes large, pointed, divergent; small or deep-water forms with only submersed, linear lvs to 0.5 cm wide; scape stout, terete, 1-15 dm; fls in 3-12 whorls, the upper staminate, on long, slender pedicels, the middle and lower perfect, on somewhat shorter, stout, recurved pedicels; bracts mostly ovate, connate below, very thin and soon withering; sep 4-12 mm, broad, blunt, appressed to the fruiting head; pet 7-15 mm; stamens 9-12 in perfect fls, 12-many in staminate ones; filaments roughened with minute scales; achenes 2-3 mm, narrowly winged on the dorsal and ventral margins only, the sides wingless, the oblique or horizontal beak often more than half as long as the width of the body; 2n=22. Marshes, ponds, and streams, in circumneutral or alkaline waters; drainage of the Mississippi R. (sens. lat.), n. to lakes Michigan and Erie, s. to Tex., N.M., and Mex., and apparently e. sporadically to Del.; Calif. June-Oct. (S. montevidensis ssp. c.; Lophotocarpus c.; L. depauperatus)
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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