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Seaweeds > Division Chlorophyta
Ruffled fan green seaweed
Udotea sp.*
Family Udoteaceae
updated Jan 13

Where seen? This fan-shaped seaweed is sometimes seen at Tuas, growing on and among coral rubble. Elsewhere also in sand.

Features: A long fan- or spatula-shaped blade (2-4cm long) with ruffled edges, in clusters of several blades. Sometimes really long ones (about 10cm) are seen growing in clumps of a few large blades. The blade is made up of a tangle of tiny filaments that give it a velvety texture and is slightly to moderately calcified. The stem that holds up the blade (stipe) is calcified.
Usually olive green, but may be bright to dark green.

According to AlgaeBase, there are 40 current Udotea species.

Sometimes confused with
other fan-shaped green seaweeds. Here's more on how to tell apart fan-shaped green seaweeds.

Human uses: Some species have anti-bacterial and anti-tumor properties.

Tuas, Oct 10

Tuas, Apr 05

Tuas, Sep 08

Tuas, Apr 08

Ruffled fan green seaweeds on Singapore shores

Photos of Ruffled fan green seaweeds for free download from wildsingapore flickr

*Species are difficult to positively identify without close examination of internal parts.
On this website, they are grouped by external features for convenience of display.

Distribution in Singapore on this wildsingapore flickr map

Udotea species recorded for Singapore
Pham, M. N., H. T. W. Tan, S. Mitrovic & H. H. T. Yeo, 2011. A Checklist of the Algae of Singapore.

  Udotea argentea
Udotea flabellum
Udotea glaucescens



  • 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].
  • 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.
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