Description ⁴

A small, much branched, unarmed procumbent herb with upto 30 cm long branches rooting at the nodes and pubescent near apex. Leaves opposite, subsessile, oblong-ovate, 1-3.5 cm x 4-10 mm, mostly glabrous or puberulous, margins entire, ± obtuse at the apex. Flowers white to pale-blue or violet, c. 8 mm long, in axillary and terminal, up to 8 cm long spikes; bracts broadly elliptic, subacute; bracteoles linear, 4-5 mm long, pubescent. Calyx 5-lobed to the middle, lobes linear, c. 2 mm long, hairy, scarious-ciliate on margins, acute. Corolla pubescent, tube c. 3 mm long, limb 2-lipped, upper lip 2-lobed, patent, lower lip shortly 3-lobed. Stamens 2 fertile and 2 staminodial, anthers oblong, ± divaricate basally. Ovary oblong, many-ovuled, hairy at tip; style filiform, c. 5 mm long. Capsule narrowly oblong, glabrous except the tip, more than 15-seeded. Seeds minute, ± orbicular.

General habitat ⁵

"Habitat and Ecology: This species is a freshwater amphibious herb. It is found in warmer climates and prefers flowing streams, but may also be found in slow-moving waters and in lakes. It is a fast-growing and fast-spreading species that out-shades and out-competes other submersed plants. This plant interferes with navigation and has been known to compete with other aggressive non-native invasive plants. Systems: Freshwater List of Habitats: 5, 5.1, 5.6, 5.7"

In MD:
"High Risk to Become Invasive; Red Alert, No Report Yet in MD" - MD Aquatic Nuisance Species Task Force

Sources and Credits

1. (c) anonymous, some rights reserved (CC BY-SA), http://commons.wikimedia.org/wiki/File:Hygrophila_polysperma.JPG
2. no rights reserved, uploaded by Ian Pfingsten
3. (c) mojopf21, some rights reserved (CC BY-NC)
4. (c) Missouri Botanical Garden, 4344 Shaw Boulevard, St. Louis, MO, 63110 USA, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/5024793
5. (c) India Biodiversity Portal, some rights reserved (CC BY), http://eol.org/data_objects/26327432

More Info

• iNat taxon page
• Atlas of Living Australia
• Biodiversity Heritage Library
• BOLD Systems BIN search
• eFloras.org
• Flora of North America (beta)
• Global Biodiversity Information Facility (GBIF)
• HOSTS - a Database of the World's Lepidopteran Hostplants
• IPNI (with links to POWO, WFO, and BHL)
• NatureServe Explorer 2.0
• SEINet Symbiota portals
• Tropicos
• USDA PLANTS database
• World Flora Online

iNat Map