Nechamandra

Scientific name

Nechamandra Planch.

Family

Hydrocharitaceae

Similar genera

Blyxa, Lagarosiphon, Najas, Vallisneria

Native distribution

Asia (India, China, Vietnam)

Species cultivated

Nechamandra alternifolia (Roxb.) Thwaites

Adventive distribution

established in Sudan and Sri Lanka

Weed status

Nechamandra alternifolia is not known to be a serious weed, though it has been prohibited as a noxious weed in one country.

Habit

submerged submerged:
(adj) (syn. submersed) under water; submerged below the water surface
stem plantstem plant:
(n) (a term used in the aquarium and pond plant trade) having an elongate stem (as opposed to a compact stem)
, attached to substrate

Brief description

Annual or perennialperennial:
(adj) (of a plant) having a life cycle of more than two years
. Stem greatly elongated, irregularly branched. Leaves alternatealternate:
(adj) (of leaves) bearing one leaf per node; placed singly on the stem at different heights
, caulinecauline:
(adj) pertaining to or belonging to the stem
, sheathed at base; leaf bladeblade:
(n) (syn. lamina) the flat, expanded part of a leaf, frond, or petal (excluding, e.g., the petiole)
elongate, veins parallel, without prominent midribmidrib:
(n) the main or central vein, line or rib in a leaf or perianth segment
; margins minutely serrated. Flowers unisexualunisexual:
(adj) (of a flower) with either stamens (male) or pistils (female) but not both; consisting of only male or female flowers
, axillaryaxillary:
(adj) in, of, or produced from an axil
; female flowers borne on elongate pedicel-like stalks (actually hypanthia) and opening at water surface; male flowers minute, numerous, abscising from small spathespathe:
(n) a large bract or bracts subtending and often enclosing an inflorescence
and opening while floating freely on water surface; sepals 3; petals absent or rudimentary. Dipersal likely by stem fragments and seed.

Natural habitat

typically found in still, temporary waters

Additional comments

This genus was originally thought to be closely related to worldwide environmental weed Lagarosiphon, but was subsequently considered to be very closely related to Vallisneria based on floral characteristics. Nechamandra is considered a serious potential environmental weed and is declared as a prohibited noxious weed by state authorities in Florida (United States), yet the basis for that declaration is unclear. Nechamandra alternifolia is very similar in appearance to Vallisneria caulescens Bailey & Muell. and V. triptera Jacobs & Frank from northern Australia. This genus is not at present known to be cultivated for aquaria or ponds.