COCAS
| Date | Clue |
|---|---|
| 2015-11-29 | Plants with intoxicating leaves |
| 2015-04-02 | Plants that are illegal to import |
| 2014-11-30 | Chewed stimulants |
| 2010-10-03 | South American shrubs with potent leaves |
| 1996-06-23 | Drug-yielding plants |
| 1995-11-07 | Imogene et al. |
| 1994-09-26 | Drug-yielding plants |