Where seen? This climber with its three-part leaves is
commonly seen twining around trees in the back mangroves. When in
bloom it turns the mangrove forest into a bridal chamber in pink!
The Malay name is Akar ketuil or Tuba laut.
According to Hsuang Keng, it was common on our coasts and by tidal
rivers including Changi, Pulau Ubin and Kranji. According to Giersen,
it grows in the back mangroves preferring areas with high freshwater
inputs and not too often inundated by tides.
Features: A shrub or scrambling
climber to 15m or more, spreading by root suckers. Stems woody, bark
smooth, dark brown, corky with orange lenticels.
Compound leaf made up of 3-5 leaflets eye-shaped (10-12cm long) dark
Flowers delicate, pale pink (1.5cm) several in a loose cluster on
a slender inflorescence (about 20cm long).
Fruits coin-like circular flat pods (3-4cm) with 1-2 seeds. The pods
are green at first, and turn brown and woody as they ripen. The pod
contains air cavities and thus floats. Although the wind might also
blow them around a fair bit.
Role in the habitat: Like other
climbers, it provides shelter for smaller creatures of the mangroves.
The plants also form an interlocking framework among trees, which
may add to strength of the forest against coastal storms. The plant
twines around trees and shrubs and can form deep "choke" marks on
trees as their trunks expand. But eventually, the trees usually prevail,
breaking the vines. Thus common derris doesn't 'strangle' trees.
According to the NParks Flora and Fauna website, it is the preferred
local food plant for caterpillars of the dark caerulean butterfly
(Jamides bochus nabonassar). The mother butterfly lays her
eggs in the space between the flower buds, or in the spaces between
the flower stalks and the axis of the flowering shoot. According to
Butterfly Circle, it is also the host plant for the Sumatran
sunbeam (Curetis saronis sumatrana), Common
Awl (Hasora badra badra), White
Banded Awl (Hasora taminatus malayana), Nacaduba
pavana singapura and Short
Banded Sailor (Phaedyma columella singa).
uses: According to Burkill, the plant roots are also used
to produce 'tuba', a poison used in poison arrow and as an insecticide,
particularly in vegetable gardening. It has some medicinal uses, and
the twinning stems are also used as rough cords. According to Geisen,
the commercial fish poison 'rotenone' or Derris dust is derived from
the tuberous roots of another South East Asian species, D. elliptica.
Derris species are best known for their use as a fish poison,
with Derris trifoliata mentioned as the weakest source of such
fish poisons. Burkill describes the use of Derris in fishing:
"When a big fish-hunt is planned, large amounts of Derris
root is pounded and soaked in water. When whole canoes, full of water
and pounded Derris, are upset into the river or pong, a very
rapid stupefying of the fish occurs, enabling them to be lifted out
of the water by hand. This is preceeded by wild attempts of the victims
to escape, in which they expose themselves to spearing, and in this
spearing is the chief excitement of the sport. After the poisoning,
the water soon becomes pure again. This of course is chiefly by diffusion,
but also because aqueous solutions of the poison decompose rather
Sungei Pandan, Jun 09
Wetland Reserve, Mar 09
Pulau Ubin, Aug
Pasir Ris, Apr 09
|Common derris on Singapore shores
- Hsuan Keng,
S.C. Chin and H. T. W. Tan. 1990, The
Concise Flora of Singapore: Gymnosperms and Dicotyledons.
Singapore University Press. 222 pp.
P. B., 1986. The
Botany of Mangroves
Cambridge University Press. USA. 419 pp.
I. H., 1993. A
Dictionary of the Economic Products of the Malay Peninsula.
3rd printing. Publication Unit, Ministry of Agriculture, Malaysia,
Kuala Lumpur. Volume 1: 1-1240; volume 2: 1241-2444.