Northern Prairie Wildlife Research Center
Aquatic and Wetland Vascular Plants of the Northern Great Plains
52. Hydrocharitaceae, the Frog's-bit Family
2. Vallisneria L. -- Eelgrass, Tapegrass, Water-celery
1. Vallisneria americana Michx.
Plants acaulescent with long, linear, ribbonlike leaves arising in tufts, fibrous-rooted,
producing short stolons from the base, often forming extensive submerged beds.
Leaves up to 1 m or more long though usually shorter, 3-12 mm wide, with
a many-nerved median band bordered by nerveless or sparsely nerved marginal
bands, blunt or rounded at the tip. Male plants producing a head of numerous
flowers within a short-stalked, 2- to 3-parted spathe borne at the base; male
flowers minute, with 3 sepals, 1(2) minute petal(s) and (1)2(3) stamens,
individually released from the spathe to float freely to the surface where they
open. Female plants bearing flowers singly on long, slender peduncles
that extend the flower to the surface; female flowers with 3 sepals,
3 minute petals and 3 prominent stigmas, sometimes with 1 or more staminodes;
ovary enclosed by a hypanthium, linear-cylindric, 2-3 cm long in flower,
enclosed at the base by the 2-cleft spathe. Fruit cylindric, curved,
4-10 cm long, many-seeded; peduncle becoming loosely coiled to draw the
fruit underwater. Jul--Sep. Uncommon though locally abundant in shallow water
of lakes in ne SD; also reported for Cherry Co., NE; occurring also in slow-moving
streams e of our range where it is common; (N.S. to MN and SD, s to FL, TX,
NM and AZ).
Submersed forms of Sagittaria spp. are sometimes mistaken for this
plant. In sterile material, the distinctive marginal bands of the leaves and
the stoloniferous habit are diagnostic for Vallisneria.
To the east of this region, V. americana is an important food for
waterfowl and other aquatic life. It is apparently limited here by high conductivities,
turbidity and unstable water conditions, and is thus not abundant enough to
be an important food source.
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Return to Family -- Hydrocharitaceae
- The Frog's-bit Family