Justicia

Scientific name

Justicia L.

Common names

water willow, spikespike:
(n) an indeterminate, unbranching inflorescence of sessile flowers or flower clusters on a usually elongated axis
justica

Family

Acanthaceae

Similar genera

Alternanthera, Epilobium, Fittonia, Hemigraphis, Hygrophila, Hypericum, Lobelia, Ludwigia, Lythrum, Pilea, Staurogyne, Veronica

Native distribution

North America, especially the United States

Species cultivated

Justicia americana (L.) Vahl

Adventive distribution

information not available

Weed status

not weedy

Habit

amphibious amphibious:
(adj) of a plant able to live on land or in water
to emergentemergent:
(adj) (syn. emersed) with parts raised out of the water; extending up out of the water
aquatic or subaquatic herb, often forming dense colonies

Brief description

Medium erect or ascending herb, rhizomatousrhizomatous:
(adj) possessing rhizomes
. Submergedsubmerged:
(adj) (syn. submersed) under water; submerged below the water surface
stems sometimes have fibrous roots; stems ± angularangular:
(adj) having projecting longitudinal angles; undulate, but sharply angled rather than gently rounded
, usually unbranched, glabrousglabrous:
(adj) without hairs or scales
. Leaves oppposite, 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
to subsessile; leaf bladeblade:
(n) (syn. lamina) the flat, expanded part of a leaf, frond, or petal (excluding, e.g., the petiole)
lanceolate or linear to ellipticelliptic:
(adj) in the form of an ellipse (oval)
or oblongoblong:
(adj) two to four times longer than wide, with +/- parallel sides
, glabrousglabrous:
(adj) without hairs or scales
; apexapex:
(n) the point farthest from the point of attachment; the tip (often pointed)
and base tapering; marginmargin:
(n) edge; rim
entireentire:
(adj) having a continuous margin that is not toothed or lobed
or shallowly crenatecrenate:
(adj) (of a margin) with shallow, rounded teeth
; midveinmidvein:
(n) the primary, usually central vein of a leaf or leaflet
distinctively white. Inflorescenceinflorescence:
(n) the arrangement of flowers on the floral axis
an axillaryaxillary:
(adj) in, of, or produced from an axil
, capitatecapitate:
(adj) terminated by an enlarged and rounded head
spike; pedunculatepedunculate:
(adj) borne on or possessing a peduncle
; densely-flowered. Flowers oppositely arranged, subtended by triangular bracts, bracts glabrousglabrous:
(adj) without hairs or scales
or sparsely pubescentpubescent:
(adj) (1) covered with short, soft hairs; (2) bearing hairs
; bracteoles similar to bracts. Flowers sessilesessile:
(adj) attached directly, without a stalk
to subsessile, orchid-like, white to light purple, often with purplish to maroon streaks; calyxcalyx:
(n) the outer whorl of the perianth; all the sepals of a flower
shortly tubulartubular:
(adj) (of a corolla, perianth, calyx tube or other structure) (1) tube-shaped; cylindrical: narrow and elongate with more or less straight sides; (2) having segments fused into a tube (of any shape)
, 5-lobed, lobes lanceolatelanceolate:
(adj) lance-shaped; widest point below the middle, tapering to the apex
to ellipticelliptic:
(adj) in the form of an ellipse (oval)
, glabrousglabrous:
(adj) without hairs or scales
, green; corollacorolla:
(n) the inner whorl(s) of the perianth; all the petals of a flower
shortly tubulartubular:
(adj) (of a corolla, perianth, calyx tube or other structure) (1) tube-shaped; cylindrical: narrow and elongate with more or less straight sides; (2) having segments fused into a tube (of any shape)
, 2-lipped, upper lip shallowly 2-lobed, erect, curved backwards, lower lip 3-lobed, lobes oblongoblong:
(adj) two to four times longer than wide, with +/- parallel sides
to oblong-oblanceolate, widely spreading.

Natural habitat

on muddy banks of ponds, rivers, streams, and lakes, in wet areas of swamps and sandy marshes, in stagnant to moderate flowing, shallow water

Additional comments

A genus comprising over 650 species, most of which are terrestrialterrestrial:
(adj) growing on land as opposed to living in water
in shaded areas or forests, typically in wet soil. Very few are aquatic species.