|
Euphorbia obesa
Pistillate
(female) specimen
with fruit.
Euphorbia obesa
Staminate
(male) specimen
with pollen. |
|
In
biology a dioecious
organism is male or
female, and
reproduces via
sexual
reproduction, being
therefore the opposite of a
hermaphrodite. Hence
dioecious organisms produce only one type of
gamete;
In botany the term dioecious
describe a plant populations
with unisexual
(not perfect)
flowers, with
reproductive
structures upon distinct individuals,
male and
female
organs do not co-occur in the
same plant.
Therefore, a pollinating
male plant bears no
fruits or
seeds, whereas a
female plant may have
fruits and
seeds. This plants must
be cross pollinated;
consequently a female plant
will only bear fruit when a
male
grows nearby, and male
plants do not bear fruit. For fruit or seeds production it is
indispensable the presence of both plants
sexes. But usually only
one male plant is needed to
pollinate several female plants.
Approximately 3-4 percent of all
flowering plants
are dioecious. Although dioecism favours
cross pollination,
there is a reduced seed
production because only half of the population (the female
plants) bear seeds.
This term is sometime incorrectly applied to individual flowers.
For example
Euphorbia obesa.
Compare with: Monoecious. |