Tonina

Scientific name

Tonina Aubl.

Common names

none

Family

Eriocaulaceae

Could be confused with

Egeria, Elodea, Eriocaulon, Hemianthus, Hydrilla, Lagarosiphon

Native distribution

South America

Species commonly cultivated

Tonina fluviatilis Aubl. (South America)

Adventive distribution

none

Weed status

information not available

Habit

submerged, floating, or emergent stem plant

Brief description

Perennial. Stems slender, branched. Leaves cauline, alternate or spiral, sessile, narrow, elongate, lanceolate to short-ovate, veins parallel, without cross-veins; margin entire. Flowers in spiny heads borne on short peduncles from leaf axils. Flowers small, unisexual; perianth segments in 2 somewhat differentiated whorls of 3; female perianth 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

A single species is in this genus, 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.