Ammannia

Scientific name

Ammannia L.

Common names

red-stem

Family

Lythraceae

Similar genera

Alternanthera, Hygrophila, Hypericum, Ludwigia, Lythrum, Mentha, Mimulus, Nesaea, Rotala

Native distribution

tropical and warm regions of world

Species cultivated

(five species for sale or trade, plus cultivated hybrids and varieties)

Ammannia baccifera L.

A. gracilis Guill. & Perrottet

A. latifolia L.

A. multiflora Roxb.

A. senegalensis Lam.

Adventive distribution

Ammannia senegalensis is naturalized in Europe and India.

Weed status

not weedy

Habit

emergentemergent:
(adj) (syn. emersed) with parts raised out of the water; extending up out of the water
, amphibiousamphibious:
(adj) of a plant able to live on land or in 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

Annual. Erect, stem commonly red, rounded in cross-section in submersedsubmersed:
see submerged
form, four-sided in emersedemersed:
see emergent
form. Leaves 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
, elongate (commonly 3-8 cm long), typically red to green. Flowers axillaryaxillary:
(adj) in, of, or produced from an axil
, solitary or in a cymecyme:
(n) a determinate, usually flat-topped or convex inflorescence in which the terminal flower blooms earliest
, actinomorphicactinomorphic:
(adj) of flowers, having radial symmetry; capable of being bisected into identifical halves along more than one axis
, sessilesessile:
(adj) attached directly, without a stalk
or stalked.

Natural habitat

wetlands

Additional comments

A genus of 24 species. Cultivated plants are submersedsubmersed:
see submerged
and/or emersedemersed:
see emergent
. Submersedsubmersed:
see submerged
plants rarely branched. Requires high levels of light and nutrients for optimal growth. Ammannia senegalensis may be differentiated from A. gracilis by the downturned recurvedrecurved:
(adj) curved downward or backward
leaves in the submersedsubmersed:
see submerged
form, although identification may be problematic. Floral characteristics do not support this distinction of two separate species, and A. gracilis may simply represent a variety of A. senegalensis.