1. Smallest flowering plants known; of the Americas
   - Wolffia columbiana

Type of: watermeal

• impenetrable
• impenetrableness
• impenetrably
• impenitence
• impenitency
• impenitent
• impenitently
• imperative
• imperative form
• imperative mood
• imperatively
• imperativeness
• imperator
• imperatorial
• imperceptibility
• imperceptible
• imperceptibly
• imperceptive
• impercipient
• imperfect
• imperfect tense
• imperfectibility
• imperfectible
• imperfection
• imperfective