Alisma triviale Pursh
Northern Water Plantain
Family - Alismataceae
Habit - Rhizomatous, perennial, emergent aquatic forb.
Stems - Absent except for inflorescence stalk.
Leaves - Basal, petiolate. Petioles stout, with spongy tissue internally. Blades to 20 cm long, broadly elliptic to ovate, simple, entire, glabrous. Venation with 1-3 pairs of main veins arcing from near the base of the midrib and rejoining near the apex, these connected by finer, angled veins running parallel to one another.
Petiole cross section.
Leaf lower surface.
Inflorescence - Erect panicles with whorled branches. Branch nodes with narrowly triangular leaflike bracts.
Flowers - Actinomorphic, 3-merous, perfect, subtended by bracts. Sepals ovate, persistent, green, often with hyaline margins. Petals to 3 mm long, significantly longer than sepals, white. Stamens 6, the filaments as long as or longer than the anthers. Pistils 10-28, in a single ring on the flat receptacle. Styles lateral.
Flower and fruits.
Ring of fruits.
Fruits - Fruits 15-24, 1.8-3.0 mm long, borne in a ring 3.5-4.5 mm in diameter, the back with 1 dorsal groove.
Flowering - May - September.
Habitat - Pond margins, creeks, sloughs, marshes, ditches, in mud.
Origin - Native to U.S.
Other info. - This aquatic species is found scattered throughout most of the state and across
most of the northern and western U.S. It has larger flowers and fruit rings than the somewhat more common A. subcordatum,
with flower petals which clearly exceed the sepals. "Larger" in this context is a
distinctly relative term - the flowers are still quite small and inconspicuous. A well-developed inflorescence can have many dozens of flowers within
a lacy network of wiry branches. The plant is typically found in open areas of mud which has been exposed by slowly receding
Plants of this genus are a food source for aquatic wildlife such as muskrats. The rhizomes are eaten as well as the leaves.
The starchy rootstocks have been cooked in the fall for human consumption.
Plants of this genus are a food source for aquatic wildlife such as muskrats. The rhizomes are eaten as well as the leaves. The starchy rootstocks have been cooked in the fall for human consumption.
Photographs taken off Hwy H., Shannon County, MO., 7-18-03 and 6-25-04 (DETenaglia); also along the Katy Trail near Dutzow, Warren County, MO, 9-15-2017, and Marais Temps Clair Conservation Area, St. Charles County, MO, 7-22-2013 (SRTurner).