Kansas Wildflowers and Grasses - American water-willow

AMERICAN WATER-WILLOW

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Justicia americana (L. ) Vahl

Woodson County, Kansas

Perennial

Height: 20-40 inches

Family: Acanthaceae - Acanthus Family

Flowering Period: June, July, August

Stems:

Erect, simple or branched, glabrous; rhizomes branched, cord-like, producing numerous stems rising to various heights according to water depth.

Leaves:

Cauline, opposite, simple; petiole 0 to .4 inch, glabrous; blade narrowly elliptic to ovate-elliptic, 1.6 to 5.5 inches long, .3 to 1 inch wide, base tapered, margins entire or obscurely wavy, tip obtuse to acute.

Inflorescences:

Axillary spikes, 10-30-flowered, .6 to 1.2 inch; peduncles 1.6 to 6.7 inches; bracts not leaf-like, triangular.

Flowers:

Calyx .2 to .25 inch, lobes (4-)5, linear-lanceolate to subulate; corolla white to pale violet or lilac and lower lip sometimes with darker spots, .25 to .6 inch, two-lipped, lower lip spreading, 3-lobed, upper lip spreading to reflexed; stamens 2, exserted.

Fruits:

Capsules clavate or cylindric, not flattened, stipitate, .3 to .7 inch long, .08 to .14 inch wide; seeds 4, brownish, round, flattened, .08 to .14 inch, covered with minute, wart-like bumps.

Habitat:

Shallow water, muddy or gravelly shorelines, and gravel bars.

Distribution:

East 1/2 of Kansas

Origin:

Native

Comments:

Named for James Justice, 18th century Scotch horticulturist and botanist. Horizontal rhizomes grow from bases of leaf-bearing stems. The following spring, terminal buds of these rhizomes produce upright shoots with adventitious roots at their bases. These shoots begin blooming in June, and new horizontal rhizomes arise at their bases. Older parts die by the end of the second year. The interlaced network of radiating rhizomes protects plants from erosion.

American water-willow flowers