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Seagrasses > Family Hydrocharitaceae
Spoon seagrass
Halophila ovalis 'complex'
Family Hydrocharitaceae
updated Mar 14

if you learn only 3 things about them ...
Spoon-shaped seagrasses come in a range of sizes. Some scientists treat them as a complex of one species.
They don't flower frequently, and the flowers are tiny.
They are believed to be among the favourite food of dugongs.

Where seen? This small oval seagrass is commonly seen on many of our shores in the North and South. Sometimes, they may form lush meadows, at other places, smaller patches. The preliminary results of a transact survey of Chek Jawa suggest it is probably among the most widely distributed seagrass in the seagrass lagoon there.

Spoon seagrass is found throughout the tropical Indo-West Pacific region and even in some parts of temperate Australia. This seagrass has one of the widest tolerance. It is found from shallow subtidal areas to the deepest waters where seagrasses can be found, 30m and deeper. It can tolerate areas with freshwater runoff and thus lower salinity, as well as hypersaline waters.

Features: The seagrass has oval, spoon-shaped leaves and is sometimes also called 'paddleweed' or fan seagrass. It comes in a wide range of sizes (0.5-1.5cm wide and 0.5-2.5cm long) and shapes from oval, to nearly oblong or spoon-shaped. The leaf edge is smooth with no serrations, there is a vein just within the leaf margin (intramarginal vein). The leaf has obvious cross veins (4-25) and is held on a long thin stalk. It has thin, smooth, white rhizomes (underground stems) about 2mm in diameter. The leaves emerge in pairs from these rhizomes. The emerging shoot is encased in a pair of transparent scales.

Sometimes confused with seaweeds that are also spoon-shaped such as the Coin seaweed (Halimeda sp.) and Fan seaweed (Avrainvillia sp.). These seaweeds don't have veins like the spoon seagrass. Coin seaweeds are also hard as they incorporate calcium in their body structure, while spoon seagrass blades are soft and flexible.

Flowers and fruits: Spoon seagrass has separate male and female plants. The flowers form at the base of the shoot but may extend to above the height of the leaves. The male flower remains low. The round fruits are tiny. In Australia this seagrass is reported to flower densely with lots of seeds setting. Several species of seagrasses look very similar and are difficult to distinguish from Halophila ovalis. These include H. minor, H. ovata and H. hawaiiana. There is some uncertainty whether all these seagrasses are actually distinct species and some scientists treat them as one species called Halophila ovalis 'complex'. H. ovalis and H. minor are recorded for Singapore.

Role in the habitat: This seagrass is among the favourite food of dugongs so it is also sometimes called Dugong grass. Studies suggest that Halophila ovalis can recover rapidly from grazing by dugong. The seagrass leaf provides a surface for small algae to grow on. Tiny snails graze on this algae. These in turn are eaten by larger creatures. In this way, seagrasses contribute to the rich biodiversity on the shores.

Status and threats: It is listed as 'Vulnerable' on the Red List of threatened plants of Singapore.

Meadow of Spoon seagrass.
Chek Jawa, Jun 09

Sentosa, Jan 06

Changi, Apr 05

Tiny algae grow on the leaves which are eaten by tiny animals like snails.
Changi, May 05

Labrador, Nov 12

Spindly female flower of the spoon seagrass?
Changi, Apr 05

Male flower?
Chek Jawa, Jan 09
Photo shared by Loh Kok Sheng on his blog.

Burnt leaves.
Pulau Sekudu, Jun 06

Chek Jawa, Sep 11

Labrador, Nov 12


Labrador, Nov 12

Spoon seagrass on Singapore shores

Photos of Spoon seagrass for free download from wildsingapore flickr

Distribution in Singapore on this wildsingapore flickr map

Pulau Pawai, Dec 09

Pulau Biola, Dec 09

Pulau Salu, Aug 10

Pulau Berkas, May 10

Pulau Senang, Aug 10



  • Tan, Hugh T.W. L.M. Chou, Darren C. J. Yeo and Peter K.L. Ng. 2007. The Natural Heritage of Singapore. Second edition. Prentice Hall. 271 pp.
  • Davison, 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.
  • Waycott, Michelle (et. al). 2004. A Guide to Tropical Seagrasses of the Indo-West Pacific. 2004. James Cook University. 72 pp.
  • Calumpong, H. P. & Menez, E. G., 1997.Field Guide to the Common Mangroves, Seagrasses and Algae of the Philippines. Bookmark, Inc., the Philippines. 197 pp.
  • Lim, S., P. Ng, L. Tan, & W. Y. Chin, 1994. Rhythm of the Sea: The Life and Times of Labrador Beach. Division of Biology, School of Science, Nanyang Technological University & Department of Zoology, the National University of Singapore. 160 pp.
  • Huisman, John M. 2000. Marine Plants of Australia University of Western Australia Press. 300pp.
  • Hsuan Keng, S.C. Chin and H. T. W. Tan.1998, The Concise Flora of Singapore II: Monoctyledons Singapore University Press. 215 pp.
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