It grows in many types of habitat, especially moist areas.

[1][2][3][4] This plant is variable in morphology, taking several forms.

In general it is an annual herb with a thin stem 3 to 50 centimeters long, growing upright or decumbent.

The oppositely arranged leaves vary in size and shape.

The tubular base of the flower is encapsulated in a hairy calyx of sepals with pointed lobes.