Aquatic and Wetland Vascular Plants of the Northern Great Plains
51. Alismataceae, the Water Plantain Family
3. Sagittaria L. -- Arrowhead, duck potato3. Sagittaria cuneata Sheld.
Emersed or emergent perennial with rhizomes and tubers, (0.5)1-6 dm tall, or to 9 dm long when emergent in deep water, often comprised of a basal rosette of thin, subulate or linear-oblong, submersed leaves (phyllodes) during juvenile stages, also commonly producing long-petioled floating leaves with small, ovate to elliptic or sagittate blades when young and submersed, generally not flowering in this condition. Emersed leaf blades sagittate or earliest 1-few sometimes oblong-elliptic, 5-20 cm long, 1-14 cm wide, the basal lobes usually shorter than the terminal one; petioles erect to spreading. Inflorescences 1-several, erect to reclining, frequently branched from lower nodes; bracts acute to acuminate or attenuate, (0.5)1-4(5) cm long; pedicels of fruiting heads ascending to spreading, 0.3-2 cm long, those of male flowers longer and more slender. Flowers male above and female below or some perfect; sepals ovate, 4-10 mm long, reflexed in flower and fruit; petals white, 7-15 mm long; filaments glabrous, about equaling or longer than the anthers. Fruiting heads globose or nearly so, 5-13 mm in diameter; achenes 2-3 mm long, dorsal wing wider than the ventral one, rounded above and usually separated from the beak by a concavity, ventral wing broadened upward and usually convex below the beak; beak erect, often obscure, 0.1-0.4 mm long. Jun--Sep. Mud or shallow water of marshes, lakes, ponds, streams and ditches; common; (N.S. to B.C., s to NY, IN, IL, n TX, NM, UT and CA).
Sagittaria cuneata, the most common arrowhead in the northern Great Plains. Similar species are distinguished mainly by achene characters. |
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