Sansevieria trifasciata ‘Black Coral’ is a stunning， almost gothic variety of Mother-in-law’s tongue， with dark green - almost black – coloring， and gray-green horizontal stripes. Like all sansevierias， this plant is famous for its air-purifying abilities， requires very little maintenance and thrives in a wide range of light conditions. They absorb carbon dioxide and release oxygen at night， so sharing your room with these plants could give you a slight oxygen boost while you sleep.