Spirodela

Scientific name

Spirodela Schleid.

Common names

giant duckweed

Family

Araceae

Similar genera

Lemna, Limnobium (seedling), Phyllanthus

Native distribution

cosmopolitancosmopolitan:
(adj) essentially worldwide in distribution

Species cultivated

Spirodela polyrrhiza (L.) Schleid.

S. punctata (G. Mey.) C.H. Thomps.

Adventive distribution

information not available

Weed status

Spirodela polyrrhiza is a serious weed in rice fields in on several continents. It has shown resistance to diquat.

Habit

free floating, small, thallus-like plant

Brief description

Small, free-floating on water surface. Reduced plant body, undifferentiated into stem and leaf. Frondfrond:
(n) (1) a term used to describe the leaves of, e.g., ferns, palms, or duckweeds; (2) a leaf-like organ (as in .e.g. some algae, such as <em>Caulerpa</em>)
broadly ovateovate:
(adj) egg-shaped in outline; generally with the broad end at or near the base
to orbicularorbicular:
(adj) circular in outline
, green above, red below, venationvenation:
(n) the arrangement of veins in a leaf
palmatepalmate:
(adj) (of leaves or venation) with lobes, leaflets, divisions or veins originating from the same point
; marginmargin:
(n) edge; rim
entireentire:
(adj) having a continuous margin that is not toothed or lobed
. Roots unbranched, 2-21 arising from center of fronds. Daughter fronds borne in two ventralventral:
(adj) of the front of an organ or the side facing or nearest the axis (syn. adaxial) (compare dorsal); upper surface
budding pouches, attached to mother frondfrond:
(n) (1) a term used to describe the leaves of, e.g., ferns, palms, or duckweeds; (2) a leaf-like organ (as in .e.g. some algae, such as <em>Caulerpa</em>)
by short stipestipe:
(n) stalk supporting leaf or leaf-like organ
. Vegetativevegetative:
(adj) (1) pertaining to or to the growth of plant organs or plant parts that have nonreproductive functions, such as leaves, roots, stems, etc.; (2) concering non sexual propagules such as tubers, turions, stem fragments, root crowns, rhizomes
turions produced near base of roots. Inflorescenceinflorescence:
(n) the arrangement of flowers on the floral axis
minute, rarely occurring, unisexualunisexual:
(adj) (of a flower) with either stamens (male) or pistils (female) but not both; consisting of only male or female flowers
, of 1 female and 2 male flowers enclosed in a membranous spathespathe:
(n) a large bract or bracts subtending and often enclosing an inflorescence
, produced from budding pouch. Dispersal by frondfrond:
(n) (1) a term used to describe the leaves of, e.g., ferns, palms, or duckweeds; (2) a leaf-like organ (as in .e.g. some algae, such as <em>Caulerpa</em>)
budding, seeds, and resting turions.

Note that Spirodela polyrrhiza fronds may aggregate or daughter frond(s) may remain attached to the parent plant, and as a result may appear to be a single-lobed frondfrond:
(n) (1) a term used to describe the leaves of, e.g., ferns, palms, or duckweeds; (2) a leaf-like organ (as in .e.g. some algae, such as <em>Caulerpa</em>)
but are not.

Natural habitat

still waters of lakes, rivers, and swamps

Additional comments

Spirodela contains three species worldwide, but only S. polyrrhiza and S. punctata are commonly cultivated for aquaria. This genus has the largest sized plants of the duckweeds and is the only genus with multiple roots arising from each frondfrond:
(n) (1) a term used to describe the leaves of, e.g., ferns, palms, or duckweeds; (2) a leaf-like organ (as in .e.g. some algae, such as <em>Caulerpa</em>)
. One species of this genus (S. punctata) has been moved to the genus Landoltia Les & D.J. Crawford based on molecular data. Spirodela polyrrhiza is larger and rounder, and has more roots (5-21) per frondfrond:
(n) (1) a term used to describe the leaves of, e.g., ferns, palms, or duckweeds; (2) a leaf-like organ (as in .e.g. some algae, such as <em>Caulerpa</em>)
than S. punctata (2-12).