( ( Note ( that ( ( ( ( ( monocot flowers ) ( ( do not ) ( have ( differentiated ( ( sepals and ) petals ) ) ) ) ) , ) and ) ( ( ( the ( showy parts ) ) ( of ( the flower ) ) ) ( ( are simply ) ( called ( ( the perianth ) ( -LRB- ( ( not ( ( calyx or ) corolla ) ) -RRB- ) ) ) ) ) ) ) ) ) . )
(ROOT (S (VP (NN Note) (SBAR (IN that) (S (S (NP (NN monocot) (NNS flowers)) (VP (VBP do) (RB not) (VP (VB have) (VP (VBN differentiated) (NP (NNS sepals) (CC and) (NNS petals)))))) (, ,) (CC and) (S (NP (NP (DT the) (JJ showy) (NNS parts)) (PP (IN of) (NP (DT the) (NN flower)))) (VP (VBP are) (ADVP (RB simply)) (VP (VBN called) (NP (NP (DT the) (NN perianth)) (PRN (-LRB- -LRB-) (NP (RB not) (NN calyx) (CC or) (NNS corolla)) (-RRB- -RRB-))))))))) (. .)))
Note that monocot flowers do not have differentiated sepals and petals, and the showy parts of the flower are  simply called the perianth (not calyx or corolla).
(ROOT (S (NP (NP (DT All)) (PP (IN of) (NP (DT the) (NNS petals)))) (ADVP (RB together)) (VP (VBP are) (VP (VBN called) (NP (DT a) (NN corolla)))) (. .)))
All of the petals together are called a corolla.