Heteranthera rotundifolia (Kunth) Griseb.

Roundleaf Mud Plantain

Heteranthera rotundifolia plant

Family - Pontederiaceae

Stems - Creeping, with well-separated nodes.

Heteranthera_rotundifolia_stemStem.

Leaf - Dimorphic. Seedling leaves linear. Main season leaves long-petiolate. Blades to 5 cm long, mostly longer than wide, lanceolate to ovate, cordate at base, tips rounded, glabrous.

Heteranthera_rotundifolia_leafLeaf.

Heteranthera_rotundifolia_leaf2Leaf abaxial.

Inflorescence - Flowers borne singly on specialized flowering stems to 12 cm long.

Heteranthera_rotundifolia_inflorescenceInflorescence.

Flower - Perianth of 6 tepals, zygomorphic, purple to white. Tube to 29 mm long, lobes to 18 mm long. 3 tepals erect, 2 spreading, 1 pendent. Central upper tepal with yellow base. Stamens 3, unequal, with glandular-hairy filaments.

Heteranthera_rotundifolia_flowerFlower.

Heteranthera_rotundifolia_flower2Perianth.

Heteranthera_rotundifolia_flower3Perianth.

Flowering - July - October.

Habitat - Open mud, shallow water.

Origin - Native to the U.S.

Other info. - This is one of the larger-flowered members of the genus found in Missouri. It can be identified by its strongly zygomorphic perianths, having three of the tepals erect. The flowers are quite attractive up close.
With proper attention to detail, all of the Missouri representatives of the genus Heteranthera can be identified to species based solely on perianth attributes.

Photographs taken at Otter Slough Conservation Area, Stoddard County, MO, 8-13-2015 (SRTurner).



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