Sansevieria Hahnii ‘Black Star’, aka Mother-in-Law's Tongue, Bird’s Nest Sansevieria, or Dwarf Snake Plant, is a compact cultivar that will stay relatively short for its whole life. This variety has dark green leaves with bright yellow edging. Known as some of the toughest houseplants, they store carbon dioxide acquired at night to use during the day and then release oxygen at night. This helps it to maximize efficiency in cleansing the air, as found in a study conducted by NASA.