Halimeda discoidea   Decaisne,  1842 (Algae)
Organism information awaits expert curation
Class: Bryopsidophyceae

Image copyrights: The Cook Islands Natural Heritage Trust

Size: Height 0.7 cm

Color: On drying, the specimen becomes creamy white in color.

The plant is cushion-like in habit, is attached to the substratum by a distinct cylindrical or sub-cylindrical holdfast. The lowermost segment is usually single and sub-cuneate in appearance. Other segments are plane and mostly discoidal measuring 0.7 cm to 1.5 cm in height and 0.6 cm to 1.4 cm in breadth. The margin of the segment is smooth. To a large extent, branching occurs trichotomously; tetrachotomy and polychotomy are also not common. Unlike in many other species the nodal region between the segments are not indistinct.

There is a central medulla surrounded by a broad cortex. The medulla comprises medullary filaments, 39.6 µm to 66 µm in diameter, branching dichotomously and trichotomously. The cortical filament is made up of three zones of utricles. The innermost utricle is greatly inflated, being 39.6 µm long and from 26.42 to 46.2 µm broad. Numerous peripheral utricles are borne on an inner utricle. In surface view a peripheral utricle measures 26.2 µm in diameter. At the node, the medullary filaments fuse in pairs. Fusion occurs involving a length of the medullary filaments which is equal to many times their breadth. Such a fusion is termed as an "extended fusion". Very fine needle-like crystals are deposited randomly in the inter-utricular portions and between medullary filaments. The needles, a few microns in thickness, measure 13.2 µm to 52.8 µm in length.

The gametangia occur in a cluster at the tip of a segment.

Synonym (s)

Common Name (s)
Economic Importance and Threats

Habitat:  Reef Associated, Coastal


• Andaman and Nicobar Islands, Andaman Islands INDIA
• Andaman and Nicobar Islands, Nicobar Islands INDIA
• Tamil Nadu, Kanniyakumari INDIA
• Lakshadweep, Bassas de Pedro (Lat: 13.5) (Long: 72.58) INDIA (Record: 12/1988) (Depth: 18-70 mts)
• Lakshadweep, Cora Divh (Lat: 13.75) (Long: 72.25) INDIA (Record: 12/1988) (Depth: 18-70 mts)
• Lakshadweep, Sesostris (Lat: 12.91) (Long: 72.08) INDIA (Record: 12/1988) (Depth: 18-70 mts)
• Maharashtra, Angria Bank (Lat: 16.45) (Long: 72.08) INDIA
• Andaman and Nicobar Islands, Katchall INDIA
• Andaman and Nicobar Islands, Great Nicobar Island INDIA

Literature Source(s)
  • Silva, PC; Basson, PW and Moe, RL (1996) Catalogue of the benthic marine algae of the Indian Ocean University of California Press 79 1259 pp Available at - NIO, Goa
  • Society for the Management of European Biodiversity Data (2009) World Register of Marine Species (WoRMS) Available at - http://www.marinespecies.org
  • Cook Islands biodiversity and natural heritage Available at - http://cookislands.bishopmuseum.org/
  • Krishnamurthy, V (2006) Key to the taxonomic identification of green and brown marine algae of India Recent advances on applied aspects of Indian marine algae with reference to global scenario. Seaweed taxonomic identification, aquaculture, resource, environment, fouling and disease Central Salt and Marine Chemicals Research Institute, Bhavnagar 1 1-146 Available at - NIO, Goa
  • Sundararajan, M; Selvaraju, C and Krishnamurthy, V (1996) On some species of Halimeda Lamour from Indian waters Seaweed Research and Utilisation Seaweed Research and Utilisation Association 18(1-2) 21-33 Available at - NIO, Goa
  • Ambiye, V and Untawale, AG (1992) Deep water marine algal flora of the submerged banks off west coast of India Oceanography of the Indian Ocean Oxford and IBH, New Delhi 247-252 Available at - http://drs.nio.org/drs/handle/2264/2975
  • Untawale, AG; Reddy, CRK and Ambiye, VD (1989) Marine algal flora of submerged Angria bank (Arabian sea) Indian Journal of Marine Sciences Scientific Publishers 18 207-209 Available at - NIO, Goa
  • Jagtap, T.G. (1992) Marine flora of Nicobar group of islands in Andaman Sea. Indian Journal of Marine Sciences National Institute of Science Communication & Information Resources 21(1) 56-58 Available at - NIO,Goa

Page last updated on:2011-09-26

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