Hygrophila

Scientific name

Hygrophila R. Br.

Common names

hygrophila, water wisteria, Indian plant, blue stricta, hygro

Family

Acanthaceae

Could be confused with

Alternanthera, Ammannia, Gymnocoronis, Ludwigia, Persicaria, Ruellia, Shinnersia

Native distribution

Asia, South America, Africa

Species commonly cultivated

Hygrophila angustifolia R. Br. (Australia, Papua New Guinea)

H. balsamica (L.) Raf. (India, Sri Lanka)

H. corymbosa (Blume) Lindau (Southeast Asia)

H. difformis (L.) Blume (India, Burma, Thailand, Malaysia, Australia)

H. guianensis Nees (Guyana, Venezuela, Bolivia)

H. polysperma (Roxburgh) T.Anderson (India, Bhutan, Central and North America)

U.S. Federal Noxious Weed: Hygrophila polysperma

Identification: The submersed form of Hygrophila polysperma can be distinguished by its short to medium, typically light green leaves with round apices. (Variegated cultivars exist.) The emersed form is more difficult to identify, but has small sessile flowers, small emersed leaves, and a capsule bearing numerous seeds.

See Hygrophila polysperma disseminule fact sheet.

Adventive distribution

Hygrophila polysperma is introduced into Mexico and southeastern United States. Hygrophila difformis is introduced into northern Australia.

Weed status

Hygrophila polysperma is is an aquatic weed on the U.S. federal noxious weed list.

Brief description

Perennial. Stem creeping or erect, rooting at lower nodes. Leaves opposite, decussate, sessile or petiolate; leaf blade entire to dissected to various degrees, lanceolate to ovate; margin sometimes serrate, sometimes highly heterophyllous between submersed and emergent forms. Inflorescence solitary to racemose, axillary. Flowers sessile or pedicellate; sepals 5, fused or distinct; corolla 5-lobed, lobes equal or 2-lipped, with adaxial lip 2-lobed, abaxial lip 3-lobed, white to yellow, purple. Dispersal by stem fragments or seeds.

Natural habitat

rivers, lakes, and wetlands

Additional comments

A large polymorphic genus with several species cultivated for aquaria and ponds. Some species have several cultivated varieties produced.