learn only 3 things about them ...
It is made of up little leaflets.
It is most commonly seen on Chek Jawa, but rarely seen
is eaten by dugongs.
The seagrass is sometimes seen in small patches on some of our Northern
shores. But on Chek Jawa and some parts of Changi, it forms extensive
meadows. The preliminary
results of a transact survey of Chek Jawa suggest it is quite
widely distributed in the seagrass lagoon there.
Fern seagrass is found only in South China Sea region including the
coasts of northern Australia. It grows in deeper waters of 10m and
deeper, although in Singapore, this seagrass can be found right up
to the edge of the rocky shore at Chek Jawa. It can tolerate a range
of conditions so it is found in a wide range of habitats.
Features: This beautiful
seagrass has tiny leaves that grow in opposite pairs on a long thin
stem, forming a flat fern-like overall shape. 10-20 pairs of leaves
may form on the stem, new leaves growing from the tip while older
leaves at the bottom drop off. Each leaf is about 2cm long and 0.4cm
wide, with tiny serrations on the edges and a small one-sided fold
at the base. (Some books refer to these leaves as leaflets). The entire
stem is about 4-6cm long. Its rhizomes (underground stems) are thin,
Sometimes confused with feathery
seaweeds. Seaweeds are not true plants and have a different internal
structure from all seagrasses.
Flowers and fruits: Fern seagrass
has separate male and female plants. The flowers form at the junction
where each tiny leaf attaches to the central stem. There may be several
flowers on a single stem. The tiny fruits are flask-shaped and may
contain up to 30 tiny seeds.
Role in the habitat: Dugongs are
known to graze on this seagrass.
Status and threats: It is listed
as 'Critically Endangered' on the Red List of threatened plants of
Fern seagrass sometimes grows right up
to the rocky shore on Chek Jawa!
Chek Jawa, Apr 08
Leaves emerge from underground stems.
Chek Jawa, Feb 02
Chek Jawa, Sep 11
Chek Jawa, Sep 11
Changi, Jul 07
one-sided fold at the base of each leaf.
Chek Jawa, Sep 03
Tiny snails grazing on algae on the leaves.
Chek Jawa, Aug 05
Bryozoans growing on
Changi, Aug 08
Tiny organisms growing on leaflet.
Changi, Nov 07
seagrass on Singapore shores
L.J., Yaakub, S.M., and Yoshida, R.L. (2007). Seagrass-Watch:
Guidelines for TeamSeagrass Singapore Participants (PDF).
Proceedings of a training workshop, National Parks Board, Biodiversity
Centre, Singapore, 24th-25th March 2007 (DPI&F, Cairns). 32pp.
seagrasses on the Seagrass-Watch website.
G.W. H. and P. K. L. Ng and Ho Hua Chew, 2008. The Singapore
Red Data Book: Threatened plants and animals of Singapore.
Nature Society (Singapore). 285 pp.
Michelle (et. al). 2004. A Guide to Tropical Seagrasses of
the Indo-West Pacific. 2004. James Cook University. 72 pp.
H. P. & Menez, E. G., 1997.Field
Guide to the Common Mangroves, Seagrasses and Algae of the Philippines.
Bookmark, Inc., the Philippines. 197 pp.
- Hsuan Keng,
S.C. Chin and H. T. W. Tan.1998, The
Concise Flora of Singapore II: Monoctyledons
Singapore University Press. 215 pp.