Sessile Fruited Arrowhead

Herbs, perennial, to 115 cm; rhizomes absent; stolons present; corms present. Leaves emersed or submersed; submersed leaves phyllodial, flattened, 30--70 cm, rarely widening into blade; emersed leaves phyllodial, flattened, or petiole triangular, 34--50 cm, blade linear to elliptic, rarely hastate to sagittate, 5--15 ´ 0.6--12 cm, basal lobes when present shorter than remainder of blade. Inflorescences racemes, of 2--8 whorls, emersed, 8--10 ´ 2--6 cm; peduncles 10--115 cm; bracts connate more than or equal to ¼ total length, ovate, 3--6 mm, delicate, not papillose; fruiting pedicels absent. Flowers to 3 cm diam.; sepals recurved, not enclosing flower; filaments dilated, shorter than anthers, pubescent; pistillate sessile to subsessile, without ring of sterile stamens. Fruiting heads 1--1.7 cm diam.; achenes obovoid to oblong, abaxially keeled, 2--3 ´ 1.3--1.6 mm, beaked; face not tuberculate, wings 1--2, ± entire, glands 1; beak lateral, recurved, 0.8--1.4 mm. 2n = 22.

Man., Ont., Que., P.E.I., Sask.; Ark., Calif., Conn., Del., D.C., Idaho, Ill., Ind., Iowa, Kans., Ky., Maine, Md., Mass., Mich., Minn., Mo., Nebr., N.H., N.J., N.Y., Ohio, Pa., R.I., Tenn., Vt., Va., Wash., W.Va., Wis.

Flowering summer (Jul--Sep).

Calcareous or brackish shallow water and shores of ponds, swamps, and rivers, occasionally in deep water; 0--1000m.

Sagittaria rigida Pursh, Fl. Am. Sept. 397. 1814
Sagittaria heterophylla Pursh, Fl. Am. Sept. 396. 1814. Not 5. heterophylla Schreb. 1811. Sagittaria heterophylla angustifolia Engelm. in A. Gray, Man. ed. 5. 494. 1867. Sagittaria heterophylla elliptica Engelni. in A. Gray, Man. ed. 5. 494. 1867.
Plants emersed and erect or nearly so, or submerged and sometimes greatly elongate ; leaves various, the phyllodia gradually tapering, the blade-bearing ones usually present, the blades 5-20 cm. long, linear, lanceolate, elliptic, or broadly ovate, 7-9-nerved, acute or cordate at the base, sometimes with 1 or 2 spreading or recurved basal lobes ; scapes 1-8 dm. long, commonly shorter than the leaves, usually bent and sometimes branched at the lower whorl of the inflorescence ; pedicels of the pistillate flowers (1 or 2 lower whorts) barely 1 cm. long, or nearly wanting ; bracts ovate, obtuse, 4-8 mm. long, united at the base ; sepals ovate or oblong-ovate, becoming 6-8 mm. long ; corolla 2-3 cm. broad or sometimes smaller ; filaments dilated, finely pubescent ; anthers very broad, shorter than the filaments ; fruit-heads 8-15 mm. in diameter, bristly by the protruding beaks of the achenes ; achenes cuneate, 3-4 mm. long, winged, the beak stout, ascending.
Type locality : Oswego River, New York.
Distribution : Quebec to Minnesota, New Jersey, Tennessee, and Nebraska.

Sagittaria rigida, the sessilefruit arrowhead or Canadian arrowhead, is an aquatic plant species native to Canada and to the United States and also naturalized in Great Britain. It grows in shallow waters along the edges of ponds and streams. What is really interesting is that it has narrow oval leaves rather than the iconic arrowhead shaped leaves of species like the Sagittaria latifolia. it has sessile female flowers, which is where it gets its name from. Its flowers are very similar to other plants in the Sagittaria family, with three white petals. It grows "potato" like tubers which can be eaten. Gathering any tubers from the Sagittaria family can be dangerous if gathered from polluted water.