( They ( ( are ( among ( ( the ( most primitive ) ) ( of ( dicotelydonous ( angiosperm plants ) ) ) ) ) ) . ) )
(ROOT (S (NP (PRP They)) (VP (VBP are) (PP (IN among) (NP (NP (DT the) (ADJP (RBS most) (JJ primitive))) (PP (IN of) (NP (JJ dicotelydonous) (NN angiosperm) (NNS plants)))))) (. .)))
They are among the most primitive of dicotelydonous angiosperm plants.
(ROOT (S (NP (NNS Angiosperms)) (VP (VBP are) (NP (NP (DT the) (ADJP (RBS most) (JJ successful)) (NN phylum)) (PP (IN of) (NP (NNS plants))))) (. .)))
Angiosperms are the most successful phylum of plants.