Justicia adhatoda

Description: Justicia adhatoda is a shrub with 10-20 lance-shaped leaves 8-9 centimeters in length by four wide. They are oppositely arranged, smooth-edged, and borne on short petioles. When dry they are of a dull brownish-green colour. They are bitter-tasting. When a leaf is cleared with chloral hydrate and examined microscopically the oval stomata can be seen. They are surrounded by two crescent-shaped cells at right angles to the ostiole. The epidermis bears simple one- to three-celled warty hairs, and small glandular hairs. Cystoliths occur beneath the epidermis of the underside of the blade. The trunk has many long opposite ascending branches, where the bark is yellowish in color. Flowers are usually white and the inflorescence shows large, dense, axillary spikes. Fruits are pubescent, and are with club-shaped capsules.

Flowering and Fruiting: March to June.

Economic Importance: Used extensively in the treatment of cough and other respiratory ailments. Liquid extract of the plant is used in many pharmaceutical formulations as an expectorant. 

Reference: https://en.wikipedia.org/wiki/Justicia_adhatoda