[Overview]
A hairless annual or perennial.
The stems have 4 ridges, branch freely, and creep or ascend.
The leaves are simple and opposite, ovate, with pinnate veins.
The leaf margin is serrated.
The flowers are borne singly in the leaf axils in the upper part of the stem; they are yellow or white, bell-shaped, with the tip divided into 5 slightly lip-like lobes.
Purple veins run through the throat inside the corolla, which has soft hairs.
There are 4 stamens.
There is a pair of bracts at the base of the flower.
The fruit is a capsule, and the seed surface has a net-like pattern.
[Cultivation]
Propagate from seed or stem cuttings.
It is weak to cold and so is treated as an annual, but it can overwinter if brought indoors to a sunny spot in winter.
It prefers sunny, well-drained soil.
For potted plants, water thoroughly once the soil has dried; for plants in the ground, rainfall is sufficient.
Fertilize sparingly; it is enough to give liquid fertilizer during the flowering period while watching how the plant is doing.
There are no particular pests or diseases.
