the plant world, the sex of an individual specimen is not
always easily defined. Sexual reproduction takes place in
flowers and these come in many forms and types. Plants have
developed several variations which has added to their
diversity and increased their prospects for survival.
stamen is the male part of a flower. It consists of a filament
(stalk) and the anther where the pollen is produced. The
pistil consists of the stigma, style and
ovary. It is the
female part of the flower and produces the seeds after
fertilization (pollination) takes place.
Many plants have "perfect" flowers which
contain both male and female parts. Some of these plants may
be fertilized by pollen produced by their own flowers. They
are said to be self-fruitful and would include tomatoes,
peaches, apricots and tart cherry. Other plants such as
apples, pears, sweet cherries and Japanese plums will not
accept the pollen from their own flowers. These plants must
have a second variety nearby to act as a pollen source and are
called non-self-fruitful plants.
plant species have separate male plants and female plants.
Holly and ginkgo trees are examples. These plants are called
dioecious and require the presence of both a male and female
for pollination to occur. That is why you must have both a
male and female holly plant to produce berries on the female.
walnut trees are
monoecious plants. They have
separate male and a female flowers but they are located on
different parts of the same plant. The silk on corn is the
female flower while the tassel which provides the pollen is
are even more mixed up. Most cucumber vines produce both male
and female flowers on the same vine (monoecious). Generally,
the first flowers will be male followed as the vine grows with
some female flowers and ending with males at the end of the
vine. Female flowers have a swelling at the base which is the
ovary that eventually becomes the pickle. Male flowers do not
have this swollen base.
In the quest for top production, plant
hybridizers have developed cucumber varieties that have either
all male or all female flowers. Commercial growers plant
mostly cultivars with only female flowers. When planting large
fields, they mix in a few seeds from a totally male variety so
that these vines will act as the pollen source.
Transfer of the pollen from the stamen to
the pistil occurs in many different ways. For some plants, it
is carried by the wind and may spread over long distances.
Other plants require that
insects such as bees crawl over the
surface of the anther and carry the pollen to the pistil of
another plant. Birds and even bats may also carry out the
function for certain species of plants around the world.
generally pollinate themselves before the flower opens.
Breezes toss the closed flower around causing the pollen to
drop from the anther to the stigma. Greenhouse grown tomatoes
often need to be artificially shaken to accomplish
fertilization since there is no wind to do the job.
Cucumbers require pollination by
Commercial growers bring hives into the fields to assure good
pollination. Greenhouse cucumbers, the so-called burpless
types, are parthenocarpic which means that they develop fruit
without having to be pollinated. That is why they are