( ( ( ( Poison ivy ) and ) ( poison oak ) ) ( both ( ( have ( ( three leafs ) ( 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 leafs)) (PP (IN per) (NP (NN stem))))) (. .)))
Poison ivy and poison oak both have three leafs 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))))) (. .)))