( ( The ( female gametophyte ) ) ( ( is ( the ( embryo sac ) ) ) . ) )
(ROOT (S (NP (DT The) (JJ female) (NN gametophyte)) (VP (VBZ is) (NP (DT the) (NN embryo) (NN sac))) (. .)))
The female gametophyte is the embryo sac .
(ROOT (S (NP (NP (DT The) (JJ amniotic) (NN sac)) (, ,) (SBAR (WHNP (WDT which)) (S (VP (VBD was) (VP (VBG sitting) (PP (IN on) (NP (NP (NN top)) (PP (IN of) (NP (DT the) (JJ flat) (NN embryo))))))))) (, ,)) (VP (VBZ envelops) (NP (DT the) (NN embryo)) (SBAR (IN as) (S (NP (PRP it)) (VP (VBZ folds))))) (. .)))