Hygrophila

Scientific name

Hygrophila R. Br.

Common names

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

Family

Acanthaceae

Similar genera

Alternanthera, Ammannia, Gymnocoronis, Ludwigia, Mentha, Mimulus, Nelsonia, Ruellia, Shinnersia, Staurogyne

Native distribution

Asia, South America, Africa

Species cultivated

Hygrophila angustifolia R. Br. [synonym of H. ringens var. ringens]

H. balsamica (L.) Raf.

H. corymbosa (Blume) Lindau

H. costata Nees [also offered under the synonyms H. guianensis Nees and H. lacutris (Cham. & Schltdl.) Nees]

H. difformis (L.) Blume

H. lancea (Thunb.) Miq. [synonym of H. ringens var. ringens]

H. odora (Nees) T.Anderson

H. pinnatifida (Dalzell) Screem.

H. polysperma (Roxburgh) T.Anderson

U.S. Federal Noxious Weed: Hygrophila polysperma

Identification: The submersedsubmersed:
see submerged
form of Hygrophila polysperma can be distinguished by its short to medium, typically light green leaves with round apices. (Variegated cultivars exist.) The emersedemersed:
see emergent
form is more difficult to identify, but has small sessilesessile:
(adj) attached directly, without a stalk
flowers, small emersedemersed:
see emergent
leaves, and a capsule bearing numerous seeds.

See Hygrophila polysperma disseminule fact sheet.

H. salicifolia (Vahl) Nees [synonym of H. ringens var. ringens]

H. stricta (Vahl) Lindau

Adventive distribution

Hygrophila corymbosa is introduced into the United States.

H. costata is introduced into Australia.

H. difformis is introduced into the United States and northern Australia.

H. polysperma is introduced into Australia, Mexico and southeastern United States; recently reported in Europe.

Weed status

Hygrophila costata and H. polysperma are significant weeds in several countries; H. polysperma is an aquatic weed on the U.S. federal noxious weed list.

Habit

submersedsubmersed:
see submerged
and emergentemergent:
(adj) (syn. emersed) with parts raised out of the water; extending up out of the water
stem plantstem plant:
(n) (a term used in the aquarium and pond plant trade) having an elongate stem (as opposed to a compact stem)

Brief description

Perennial. Stem creeping or erect, rooting at lower nodes. Leaves oppositeopposite:
(adj) (of leaves) two leaves per node; in pairs on opposite sides of an axis
, decussatedecussate:
(adj) arranged along stem in pairs, with each pair at right angles to the pairs above and below
, sessilesessile:
(adj) attached directly, without a stalk
or petiolatepetiolate:
(adj) relating to or in the form of a petiole; bearing petioles
; leaf bladeblade:
(n) (syn. lamina) the flat, expanded part of a leaf, frond, or petal (excluding, e.g., the petiole)
entireentire:
(adj) having a continuous margin that is not toothed or lobed
to dissecteddissected:
(adj) (of leaves) +/- deeply divided, cut, or lobed, including being compound
to various degrees, lanceolatelanceolate:
(adj) lance-shaped; widest point below the middle, tapering to the apex
to ovateovate:
(adj) egg-shaped in outline; generally with the broad end at or near the base
; marginmargin:
(n) edge; rim
sometimes serrateserrate:
(adj) (of a leaf margin) bearing sharp teeth pointing forward or to the apex
, sometimes highly heterophyllousheterophyllous:
(adj) with dissimilar leaves on the same plant; often occurs on plants with both submersed and emersed leaves
between submersedsubmersed:
see submerged
and emergentemergent:
(adj) (syn. emersed) with parts raised out of the water; extending up out of the water
forms. Inflorescenceinflorescence:
(n) the arrangement of flowers on the floral axis
solitary to racemoseracemose:
(adj) (1) bearing racemes; in the form of a raceme; (2) raceme-like
, axillaryaxillary:
(adj) in, of, or produced from an axil
. Flowers sessilesessile:
(adj) attached directly, without a stalk
or pedicellatepedicellate:
(adj) borne on a pedicel
; sepals 5, fused or distinct; corollacorolla:
(n) the inner whorl(s) of the perianth; all the petals of a flower
5-lobed, lobes equal or 2-lipped, with adaxialadaxial:
(adj) pertaining to the side facing toward the axis, as in the upper surface of a leaf
lip 2-lobed, abaxialabaxial:
(adj) the side facing away from the axis, as in the underside of a leaf
lip 3-lobed, white to yellow, purple. Dispersal by stem fragments, rooting from individual leaves, or seeds.

Natural habitat

rivers, lakes, and wetlands

Additional comments

A large polymorphicpolymorphic:
(adj) displaying multiple forms (of, e.g., an organ) in one organism
genus with several species cultivated for aquaria and ponds. Some species have several cultivated varieties produced.