Species commonly cultivated
Tonina fluviatilis Aubl. (South America)
information not available
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.
mostly in relatively slow flowing or still waters