桃園石龍尾

植物簡介

An aquatic herbaceous plant with emergent and submerged forms. The simple leaves are arranged on the stem in opposite pairs or in whorls of 3. They are lanceolate-elliptic to ovate-lanceolate in shape. The leaf margin is toothed with rounded or pointed teeth. The submerged leaf form is less rigid and bigger in size as compared to the emergent leaf form. The leaves are green with a purple underside, under high light conditions, the submerged leaves turn red. The bluish purple, white or pink, tubular flowers (10.5 to 13.5 mm long) are only produced when the plant is above the water surface. They may be solitary in the leaf axils or in terminal or axillary raceme inflorescences up to 15 cm long. Fruit is a brown, egg-shaped to ellipsoid and compressed capsule (5 to 6 mm long).