( ( ( ( Poison ivy ) and ) ( poison oak ) ) ( both ( ( have ( ( three leaflets ) ( per stem ) ) ) . ) ) )
(ROOT (S (NP (NP (NN Poison) (NN ivy)) (CC and) (NP (NN poison) (NN oak))) (DT both) (VP (VBP have) (NP (NP (CD three) (NNS leaflets)) (PP (IN per) (NP (NN stem))))) (. .)))
Poison ivy and poison oak both have three leaflets per stem.
(ROOT (S (NP (NN Poison) (NN ivy)) (ADVP (RB typically)) (VP (VBZ has) (NP (NP (CD three) (NNS groups)) (PP (IN of) (NP (NNS leaves))))) (. .)))