( ( A ( pollen grain ) ) ( ( ( is ( a ( ( -LRB- ( A -RRB- ) ) male ) ) ) gametophyte ) . ) )
(ROOT (S (NP (DT A) (NN pollen) (NN grain)) (VP (VBZ is) (NP (DT a) (PRN (-LRB- -LRB-) (NP (NNP A)) (-RRB- -RRB-)) (NN male)) (ADVP (RB gametophyte))) (. .)))
A pollen grain is a (A) male gametophyte.
(ROOT (S (NP (NP (DT A) (NN grain)) (PP (IN of) (NP (NN pollen)))) (VP (MD can) (VP (VB be) (VP (VBN described) (PP (IN as) (NP (NP (DT a) (JJ tiny) (JJ male) (NN gametophyte)) (VP (VBN enclosed) (PP (IN in) (NP (DT a) (JJ tough) (NN capsule))))))))) (. .)))