( ( ( ( Allergic reactions ) ( to ( three ( native ( American plants ) ) ) ) ) ( -- ( ( ( ( ( ( ( poison ivy ) , ) ( poison oak ) ) , ) and ) ( ( ( poison sumac ) , ) ( ( all members ) ( of ( the ( plant ( genus Toxicodendron ) ) ) ) ) ) ) -- ) ) ) ( ( have ( ( been ( sources ( of misery ) ) ) ( for ( many centuries ) ) ) ) . ) )
(ROOT (S (NP (NP (NP (JJ Allergic) (NNS reactions)) (PP (TO to) (NP (CD three) (JJ native) (JJ American) (NNS plants)))) (PRN (: --) (NP (NP (NN poison) (NN ivy)) (, ,) (NP (NN poison) (NN oak)) (, ,) (CC and) (NP (NP (NN poison) (NN sumac)) (, ,) (NP (NP (DT all) (NNS members)) (PP (IN of) (NP (DT the) (NN plant) (NNS genus) (NN Toxicodendron)))))) (: --))) (VP (VBP have) (VP (VBN been) (NP (NP (NNS sources)) (PP (IN of) (NP (NN misery)))) (PP (IN for) (NP (JJ many) (NNS centuries))))) (. .)))
Allergic reactions to three native American plants -- poison ivy, poison oak, and poison sumac, all members of the plant genus Toxicodendron -- have been sources of misery for many centuries.
(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))))) (. .)))