It is an erect
biennial (occasionally
annual) plant growing up to 1.5 m tall, with a glaucous blue-green stem. The leaves are arranged in
decussate opposite pairs, and are lanceolate, 5–15 cm long and 1-2.5 cm broad,
glaucous blue-green with a waxy texture and pale greenish-white midrib and veins. The flowers are green to yellow-green, 4 mm diameter, with no petals. The seeds are green ripening to brown or grey, produced in globular clusters 13–17 mm diameter of three seeds compressed together. ==Chemical characteristics==