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Seaweeds > Division Rhodophyta > Family Gracilariaceae > Genus Gracilaria
Knobbly agar-agar seaweed
Gracilaria salicornia
Family Gracilariaceae
updated Jan 13

Where seen? Small clumps of this distinctive knobbly seaweed is sometimes seen on many of our shores, on bare sand or attached to rocks and coral rubble.

Features: 'Stem' made up of succulent club-shaped structures (each about 1-3cm long) joined together. May form loose clusters of long 'stems' (10-15cm)'. Or dense clumps of short 'stems' (1-3cm) growing low against rock or coral rubble. Black or brownish with only the slightest tinge of red, sometimes yellowish brown.

Human uses: It is used as animal feed, and fertiliser for coconut trees and coffee bushes in China, India and Sri Lanka. Like other Gracilaria species, it is also a source of agar-agar and is eaten as a jelly and as a 'crunchy' snack. Other uses include as an insect repellant and to treat knee joints, sores, heart complaints, stomach and intestinal disorders. It is reported to have anti-bacterial and anti-tumor properties.

Chek Jawa, May 05

Chek Jawa, Feb 12

Chek Jawa, Feb 12

Tuas, Jul 06

Pulau Semakau, Aug 11

Tanah Merah, Dec 09

Labrador, Jun 05

*Seaweed species are difficult to positively identify without microscopic examination.
On this website, they are grouped by external features for convenience of display.

Knobbly agar-agar seaweeds on Singapore shores

Photos of Knobbly agar-agar seaweeds for free download from wildsingapore flickr

Distribution in Singapore on this wildsingapore flickr map

Pulau Pawai, Dec 09

Links References
  • Lee Ai Chin, Iris U. Baula, Lilibeth N. Miranda and Sin Tsai Min ; editors: Sin Tsai Min and Wang Luan Keng, A photographic guide to the marine algae of Singapore, 2015. Tropical Marine Science Institute, 201 pp.
  • Pham, M. N., H. T. W. Tan, S. Mitrovic & H. H. T. Yeo, 2011. A Checklist of the Algae of Singapore, 2nd Edition. Lee Kong Chian Natural History Museum, National University of Singapore, Singapore. 99 pp. Uploaded 1 October 2011. [PDF, 1.58 MB].
  • 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.
  • 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.
  • Trono, Gavino. C. Jr., 1997. Field Guide and Atlas of the Seaweed Resources of the Philippines.. Bookmark, Inc., the Philippines. 306 pp.
  • Burkill, 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.
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