2. Heteranthera
Ruíz & Pav. (mud plantain)
(Horn, 1985)
Plants
annual or perennial. Stems slender or stout, sometimes rooting at the nodes.
Leaves dimorphic (except in H. dubia), the submerged and floating leaves
linear, lacking petioles, the emergent leaves oblong to reniform, petiolate.
Stipules usually present. Flowers 1–10, single or in loose spikes, these
sessile or stalked, partly or mostly covered by the spathe. Perianth fused
below the middle. Stamens 3. Fruits slender, thin‑walled capsules to 2 cm
long. Seeds numerous (7–30 in H. dubia), 0.5–1.5 mm long, with 8–22
longitudinal ribs.
Twelve
species, North America to South America, West Indies, Africa.
The
flowers of our species all open early to midmorning and, except for those of H.
dubia, they are closed by midafternoon.