There are four introductory role that flower may have : sepals , which protect the bud of an unopened blossom ; petals , which may help to pull insects and animals ; the androecium , the male reproductive part of a flower ; and the gynoecium , the female part of the bloom . If a flower has all four , it is regard both consummate and perfect , perfect because it has all the division for replication . bloom that do n’t possess both male and distaff share , then , are uncomplete and imperfect . All imperfect flowers are unisexual .
Monoecious
Imperfect flowers are by nature unisexual as fight to perfect flower , which are bisexual ( hermaphrodite and androgynous ) . lack both male and female part in one flower , a plant life might still create male and female parts on separate flush . The male flower are staminate , having stamen to produce pollen , and the distaff flowers are pistillate with a pistil to get the pollen . When a plant does this , it is monecious . " Monoecious " comes from Greek beginning and intend one home . A begonia is monoecious . So is corn and the walnut tree .
Dioecious
Some flora raise neither androgynous flowers nor have both manlike and distaff flowers on one plant . Instead , a plant life is either male or distaff with either all pistillate ( female ) blossom on a industrial plant or all staminate ( male person ) flowers . To get fruit or seed , both manful and distaff plants must live near one another , since the male plant is needed to produce sperm - containing pollen to pollinate female blossom so that they can raise fruit and seed . " Dioecious " mean double house . Holly , willow tree and poplar Sir Herbert Beerbohm Tree are dioecious .
Changeable Flowers and Plants
Not all imperfect flowers and plants rest male or distaff . Some start off as one sex , as if they are dioecian plants , then begin producing bisexual flush . The cuke grow flowers this agency . First it grows male flowers , then becomes epicene . After this phase , the Cucumis sativus produces distaff efflorescence . at last , some cucumbers grow flowers that create yield even without pollenation . Such flower are parthenocarpic . " Parthenocarpic " think of virgin fruit . Cornell University has developed a parthenocarpic summertime squash line . The grandness of parthenocarpic flowers lies in the possibility of getting yield even when pollinator like bees are n’t around .
