the Sausage Tree at Parrot Jungle Island
click to enlarge
Tree, Kigelia africana, is a fairly inconspicuous tree when grown amongst
other trees, even though it can reach a height of 40 to 50 feet.
Here in South
Florida, one doesn't normally realize how many Sausage Trees are planted
in our area unless the distinctive sausage-type fruit is hanging on the
tree. Finding a tree with fruit is uncommon because the pollinator from
its native habitat, a fruit bat, does not occur in South Florida.
are native to Africa, where they are found throughout the sub-Saharan
region. The fruits are often quite large and can resemble two-foot long
sausages. They are wood-like and not at all palatable. Some native Africans
brew beer from the fermented fruit, and the fruit is also utilized to
prepare concoctions that cure a multitude of ailments from snake bites
to skin problems.
open stamens and
(which may contain up to a teaspoonful of nectar) are visited at night
in their native habitat by nectar feeding bats. During this visit the
bats inadvertently pollinate the flowers by brushing against the stamens
(the male part of the flower that holds the pollen) and getting pollen
on their head. The pollen that is on the bat's head is then brushed onto
the pistil (the female portion of the flower) of the next Sausage Tree
flower that is visited.
Sausage Trees are self-incompatible: pollination and fruit set will only
be successful if pollen from a different Sausage Tree is carried to the
pistil of another. Since there are no nectar feeding bats in South Florida,
these trees are rarely seen with fruit. However, when a tree is found with
fruit and they are not the progeny of hand pollination, they were probably
visited by the native Red Bellied Woodpecker or the Spot Breasted Oriole.
These two birds sometimes visit the Sausage Tree in the evening just as
the flowers are beginning to open, apparently looking for insects that
are attracted by the nectar found inside the flower. The head of the Woodpecker
is the right size to pick up pollen from one flower and carry it to another,
similar to the way the bats do. The Spot Breasted Oriole, which was introduced
from Mexico and has naturalized in South Florida, is the same size as
the Woodpecker and also causes pollination.
open and ready
to be pollinated
pollination of this tropical tree can also be done by hand. Flowers can
be collected from another tree on the day before they open and the pollen
will be viable for several days if kept in an airtight dry container and
refrigerated. The flowers open in the evening and the pistil is receptive
from early evening to mid morning the next day. Early in the night (usually),
the entire corolla with the stamens attached will drop off leaving only
the pistil attached to the ovary. Place the pollen from the collected
flower on to the open pistil. The pollen can be brushed on using a toothpick
or the entire stamen from the collected flower can be used as a pollination
tool. The latter seems the easiest if there is enough pollen for all the
flowers to be pollinated.
loking for insects
It is always
a good idea to pollinate the tree over several days. Sometimes the pollen
doesn't take or only a small percentage of the flowers pollinated will
actually set fruit. After successful pollination, the newly forming fruit
can be seen after three or four days. The fruit can take about a month
to reach full size and many trees have a unique shape and size of fruit.
If left on the tree, the fruits will begin to drop off in 10 to 12 months.
The seeds are generally viable and can sometimes germinate while still
inside the fruit.
In Africa the
leaves are eaten by elephants and kudu. Nyla, kudu, impala, grey duiker,
and domestic stock eagerly eat the flowers. Bushpigs are known to eat