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Seagrasses > Family Cymodoceaceae
Noodle seagrass
Syringodium isoetifolium

Family Potamogetonaceae

updated Mar 14

if you learn only 3 things about them ...
This seagrass is rarely seen on our shores.
It doesn't flower frequently, and the flowers are complex.
It is eaten by dugongs.

Where seen? This seagrass is abundant on Pulau Semakau, growing among the more dominant Tape seagrass (Enhalus acoroides), and on Cyrene Reef.

Noodle seagrass is found throughout the tropical Indo-West Pacific region. Elsewhere, it can form thick tall stands without any other seagrass species. It can also grow among other seagrasses species, where it is then smaller. It is rarely found in shallow intertidal areas. It appears to respond rapidly to increased nutrient availability.

Features: Leaves of those seen were 5-10cm long, but elsewhere, they can grow to 50cm long. The seagrass has tubular leaves much like a thick noodle! Unlike other seagrasses that are flat, noodle seagrass is circular in cross-section. The leaves have a smooth pointed tip. The rhizomes (underground stems) are slender (1.5mm in diameter). Shoots emerge from these rhizomes, each shoot with 2-3 leaves, the lower portions encased in a sheath. Longer shoots tend to be branched and found in calmer waters. As the leaves contain air cavities, they float easily when detached. Older leaves tend to break off as they become brittle. Elsewhere, these may form dense rafts that float and wash ashore.

Sometimes confused with Needle seagrass (Halodule sp.). While both are long and narrow, noodle seagrass, however, is cylindrical like plastic tubing or noodles, while needle seagrass is flat like a ribbon.

Flowers and fruits: Noodle seagrass has separate male and female plants. The flowers form a complex inflorescence (called a cyme). Each flower forms in a branching array on a stem. The fruit forms a small nut that is hard and beaked. An inflorescence with mature seeds may break off and float away some distance.

Role in the habitat: Dugongs graze on this seagrass where there are no Halophila or Halodule seagrasses available. So it is also sometimes called Dugong grass.

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

Pulau Semakau, Mar 05

Pulau Semakau, Jun 05

Pulau Semakau, Jun 05

Terumbu Semakau, May 10

Cyrene Reef, Oct 08

Cyrene Reef, Aug 11

Noodle seagrass on Singapore shores

Photos of Noodle seagrass for free download from wildsingapore flickr

Distribution in Singapore on this wildsingapore flickr map

Other sightings on Singapore shores

Tanah Merah Ferry Terminal, Jun 22
Photo shared by Vincent Choo on facebook.

Links References
  • 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.
  • Hsuan Keng, S.C. Chin and H. T. W. Tan.1998, The Concise Flora of Singapore II: Monoctyledons Singapore University Press. 215 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.

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