Northern Prairie Wildlife Research Center
Aquatic and Wetland Vascular Plants of the Northern Great Plains
51. Alismataceae, the Water Plantain Family
3. Sagittaria L. -- Arrowhead, duck potato
4. Sagittaria graminea Michx.
Emergent to emersed perennial or perhaps usually annual in our range, producing
rhizomes well after flowering in first year plants. Leaves variable depending
on degree of submergence and age of plant, submersed plants with the earliest
leaves comprising a rosette of phyllodes, these tapelike, to 1 cm wide, acute-tipped,
often absent by flowering time; emergent leaves or leaves of emersed
plants with blades elliptic to linear-oblong, never sagittate, 3-20 cm long,
0.5-3 cm wide, acute or attenuate to the blunt tip. Inflorescences 1-few,
shorter than to exceeding the leaves, simple, with 2-6(9) whorls of flowers;
bracts triangular-ovate, connate in the lower 1/2, 2-8 mm long; pedicels
slender to filiform, 1-4 cm long, ascending to spreading. Flowers usually
male above and female below, rarely all of one sex; sepals ovate, 3-5
mm long, reflexed in fruit; petals white, about equaling to over 2X the
sepal length; filaments equaling to longer than the anther, puberulent.
Fruiting heads globose or subglobose, 5-12 mm across; the receptacle
often conspicuously spongy-thickened; achenes 1-2 mm long, prominently
winged, the dorsal wing rounded over the top of the achene and continuous with
the ventral wing; beak minute and projecting laterally or absent. Jun--Sep.
Mud or shallow water of marshes, ponds and ditches; uncommon in NE and rarely
n into SD, probably as a temporary introduction by waterfowl; (Labr. and Newf.
to SD, s to FL and TX; also Cuba).
Previous Section -- Sagittaria cuneata Sheld.
Return to Family -- Alismataceae -
The Water Plantain Family
Next Section -- Sagittaria latifolia Willd.