( And ( ( while ( ( poison ( oak ( and ( poison ivy ) ) ) ) ( do ( tend ( to ( have ( three-leaf clusters ) ) ) ) ) ) ) ( ( , ( ( ( poison ivy ) ( can ( have ( ( ( ( up to ) nine ) leaves ) ( per cluster ) ) ) ) ) , ) ) ( ( poison oak ) ( ( may ( have ( ( ( ( as ( many ( as five ) ) ) , ) and ) ( ( poison sumac ) ( usually ( ( has seven ) ( to ( 13 ( small leaves ) ) ) ) ) ) ) ) ) . ) ) ) ) )
(ROOT (S (CC And) (SBAR (IN while) (S (NP (NN poison) (NN oak) (CC and) (NN poison) (NNS ivy)) (VP (VBP do) (SBAR (S (VP (VBP tend) (S (VP (TO to) (VP (VB have) (NP (JJ three-leaf) (NNS clusters))))))))))) (PRN (, ,) (S (NP (NN poison) (NN ivy)) (VP (MD can) (VP (VB have) (NP (NP (QP (IN up) (TO to) (CD nine)) (NNS leaves)) (PP (IN per) (NP (NN cluster))))))) (, ,)) (NP (NN poison) (NN oak)) (VP (MD may) (VP (VB have) (NP (NP (QP (RB as) (JJ many) (IN as) (CD five))) (, ,) (CC and) (NP (NP (NN poison) (NN sumac)) (VP (ADVP (RB usually)) (VBZ has) (NP (CD seven)) (PP (TO to) (NP (CD 13) (JJ small) (NNS leaves)))))))) (. .)))
And while poison oak and poison ivy do tend to have three-leaf clusters, poison ivy can have up to nine leaves per cluster, poison oak may have as many as five, and poison sumac usually has seven to 13 small leaves.
(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))))) (. .)))