From Planet X
1. Lasting or living for two years. 2. Happening every second year. 3. Having a life cycle that normally takes two growing seasons to complete. 4. An event that occurs every two years. 5. A plant that normally requires two seasons to complete its life cycle, growing usually as a rosette in the first season and producing flowers and fruits and then dying in the second season. 6. A perennial plant, such as the English daisy, cultivated as a biennial.