Tonina

Scientific name

Tonina Aubl.

Family

Eriocaulaceae

Similar genera

Egeria, Elodea, Eriocaulon, Hydrilla, Lagarosiphon, Syngonanthus

Native distribution

South America

Species cultivated

Tonina fluviatilis Aubl.

Adventive distribution

none

Weed status

information not available

Habit

submerged, floating, or emergentemergent:
(adj) (syn. emersed) with parts raised out of the water; extending up out of the water
stem plant

Brief description

Perennial. Stems slender, branched. Leaves caulinecauline:
(adj) pertaining to or belonging to the stem
, alternatealternate:
(adj) (of leaves) bearing one leaf per node; placed singly on the stem at different heights
or spiral, sessilesessile:
(adj) attached directly, without a stalk
, narrow, elongate, lanceolatelanceolate:
(adj) lance-shaped; widest point below the middle, tapering to the apex
to short-ovate, veins parallel, without cross-veins; marginmargin:
(n) edge; rim
entireentire:
(adj) having a continuous margin that is not toothed or lobed
. Flowers in spiny heads borne on short peduncles from leaf axils. Flowers small, unisexualunisexual:
(adj) (of a flower) with either stamens (male) or pistils (female) but not both; consisting of only male or female flowers
; perianthperianth:
(n) collective term for the calyx and corolla of a flower; also used for floral whorl(s) in which the calyx and corolla cannot be resolved; any of the leaves or bracts surrounding the sex organs of bryophytes
segments in 2 somewhat differentiated whorls of 3; female perianthperianth:
(n) collective term for the calyx and corolla of a flower; also used for floral whorl(s) in which the calyx and corolla cannot be resolved; any of the leaves or bracts surrounding the sex organs of bryophytes
segments fringed with hairs; inner segments minute. Dispersal presumably by seeds or stem fragments.

Natural habitat

mostly in relatively slow flowing or still waters

Additional comments

This genus contains a single species, Tonina fluviatilis. Numerous varieties of this plant (varying in leaf dimensions) are traded, usually under the name of the river system from which they were originally collected.