Heteranthera multiflora (Griseb.) C.N. Horn

Mud Plantain

© SRTurner

Family - Pontederiaceae

Habit - Annual emergent aquatic.

Stem - Creeping, with well-separated nodes.

	Stem.
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	Stem and plant.
© SRTurner

Leaves - Dimorphic. Seedling leaves linear. Main season leaves long-petiolate. Blades to 5 cm, often wider than long, reniform to orbicular, deeply cordate at base, tips broadly rounded, glabrous.

	Leaves.
© SRTurner

	Leaf adaxial.
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	Leaf abaxial.
© SRTurner

Inflorescences - Produced on specialized flowering stems, sessile, exserted up to 3x spathe length.

	Inflorescence.
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	Inflorescence.
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Flowers - Perianth of 6 tepals, zygomorphic, purple (rarely white), with tube to 12 mm long, lobes to 6 mm long. Upper 5 tepals clustered, spreading to ascending in fanlike array. Central erect tepal deeper purple at base, with two pale yellow spots. Lower tepal pendent, narrower than others. Stamens 3, unequal, with filaments densely pubescent with purple hairs.

	Flowers.
© SRTurner

	Flowers.
© SRTurner

Fruits - Slender, thin-walled capsules, to 2 cm. Seeds numerous.

	Fruits.
© SRTurner

Flowering - July - October.

Habitat - Open mud, shallow water, agricultural ditches.

Origin - Native to the U.S.

Lookalikes - Other members of the Heteranthera genus.

Other info. - This plant is relatively uncommon in Missouri, being reported from a few widely scattered locations. Its distribution in the continental U.S. is restricted to a few south-central states and a few disjunct populations on the eastern seaboard.

Like all members of the genus, H. multiflora grows in very wet places. It can be distinguished from its generic siblings by having a distinct stem, a multi-flowered inflorescence, and purple hairs on the stamen filaments.

Photographs taken at Otter Slough Conservation Area, Stoddard County, MO, 8-13-2015 and 9-11-2019, near Neelyville, Butler County, MO, 8-27-2015, and near I-70 and Missouri River, St. Louis County, MO, 9-7-2017 (SRTurner).