Vegetative plants. Key characteristics: opposite leaves with prominent white midveins.
Flowering plant. Key characteristics: stems are red and contain a white milky sap. Leaves are opposite with entire margins.
Flower. Key characteristics: color ranges from white to purple; flowers occur in the terminal portion of the plant and upper leaf axils.
Mature fruit and seed. Key characteristics: long hairs attached to the flat seed are easily detached. Seed are flattened, oval-shaped and have a length of approximately 7.0 to 8.0 mm.
Life cycle: perennial.