Northern Prairie Wildlife Research Center
Aquatic and Wetland Vascular Plants of the Northern Great Plains
51. Alismataceae, the Water Plantain Family
2. Echinodorus Rich. -- Burhead
1. Echinodorus rostratus (Nutt.) Engelm.
Fibrous-rooted annual or perennial 2-6 dm tall, emersed to emergent or sometimes
submersed with floating leaves and then nonflowering. Leaves with blades
broadly ovate to ovate-lanceolate, more oblong and thin-textured on submersed
ones, mostly 3-10 cm long, 1-6 cm wide, rounded at the tip, truncate to cordate
or broadly cuneate at the base, gradually tapered and decurrent on the petiole
on submersed leaves; petioles trigonous (broadly winged on submersed
leaves), mostly longer than the blades. Inflorescence oblong, surpassing
the leaves, usually with whorls of 3 branches from lower nodes of the scape,
the flowers in whorls of 3-9, the whorls of branches and flowers subtended by
spreading, lance-subulate bracts to 10 mm long. Flowers perfect,
usually nonshowy; sepals broadly ovate, 4-5 mm long, reflexed in fruit;
petals white, from shorter than the sepals to 9 mm long; stamens
usually 12; pistils numerous and crowded, long-styled. Fruiting heads
globose, 4-6 mm in diameter, appearing burlike due to prominent style beaks;
achenes somewhat laterally compressed but turgid, 2.5-3.5 mm long including
the straight to curved style beak, strongly ribbed lengthwise on the body. Jul--Sep.
Shores, mud flats and alluvial bars, sometimes in shallow water; c and se SD
and e NE, principally along the Missouri R. drainage; (DE to IL and SD, s to
FL, TX and into Mex; also Ont. and CA).
Previous Section -- Alisma plantago-aquatica L.
Return to Family -- Alismataceae -
The Water Plantain Family
Next Section -- Sagittaria brevirostra Mack. &