Heteranthera callifolia Rchb. ex Kunth

Global description

Heteranthera callifolia is a vivacious aquatic herb with immersed stolons and tufted leaves, erect above the water. The heart-shaped leaves borne by a long upright petiole have a characteristic horizontal habit. The inflorescence, discreet from the petiole, is a short cyme of some small white flowers. The fruit is an elongated and pointed capsule. The seeds are tiny, yellow-brown.

General habit

A stoloniferous vivacious aquatic plant with submerged stems and tufts leaves above the surface of the water up to about 30 cm in height.

Underground system

The roots are fasciculate. The plant emits stoloniferous stems.

Stem

The stems are immersed cylindrical, glabrous. They develop as stolons and take root at the nodes in the substrate.

Leaf

The leaves are simple and alternate, tufted. The petiole is 25 cm long, cylindrical, hollow, sheathing at the base. The lamina is broad, oval to lanceolate, cordiform to rounded at the base and narrowed in corner at the top. Thin and glabrous on both sides, it is 2 to 7 cm long and 1 to 5 cm wide. The margin is entire. It presents numerous slender nerves from the base, in an arcuate-parallel venation. The lamina is typicaly horizontal.

Inflorescence

The inflorescence is a cyme of 3 to 10 white flowers from the emerged part of the petiole.

Flower

The flowers are small, sessile, each sheathed in a bract. They consist of a tube 5 mm long and 6 oblong lobes veined 4 mm long. The flowers may open or not, and when they do not open they are self-fertilizing. Stamens are 3 but they can be reduced to one in the case of cleistogamous flowers (those that do not open).

Fruit

The fruit is a fusiform capsule. Its surface is finely chagrined.

Seed

The seed is tiny, 0.2 mm long. It is ellipsoid, depressed at the top, decorated with 10 longitudinal wings, short and thin. It is yellow to light brown.

https://www.gbif.org/species/2766109