Possible Clues:

• What's found in cup -- a soup that could poison you
• Dress ___ (impersonate)
• This makes us poisonous about Father
• Secretary in the States is a sap
• Poison found in university, juice knocked over
• Tree with poisonous sap
• In a higher position since climbing the Javanese tree
• Tree juice rises after mid-January
• A sup of poison
• In the group a sequoia tree!