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Order Bryopsidales

Family Udoteaceae

Thallus coenoctic, filaments froming a flat, blade-like thallus, usually calcified. Cells containing chloroplasts and amyloplasts (storage bodies).

Genus Udotea J. V. Lamouroux 1812: 186

Thallus of erect, calcified blades and stalks and uncalcified rhizoidal holdfasts. Anatomy of filaments; stalk of longitudinal siphons with cortex formed by lateral branches, blades of dichotomously-branched siphons with various degrees of branching that may be species-specific. Reproduction by release of filament contents into gametangia; thallus thought to die after gamete release. A tropical-subtropical genus with about 39 currently recognised species (Guiry & Guiry 2014).

Udotea orientalis A. Gepp & E.S. Gepp 1911: 119-120

Thallus green, erect, fan-shaped or rounded, calcified and stiffish, 20-40 mm tall, with short stipe (5-15 mm) and holdfast of dense rhizoids. Blade usually with concentric lines, margin often split. Filaments of blade about 40 µm in diameter, tightly interwoven, dichotomously-branched and with constrictions but lacking lateral outgrowths.

Collections, ecology and regional distribution

From Hluleka northward, common in northern KwaZulu-Natal (46-58). Attached to rock in pools, sublittoral fringe and sublittoral zone, as solitary individuals or groups.

World distribution: On the east African coast through Mozambique to Somalia; fairly widespread in the Indo-West Pacific (see references in Guiry & Guiry 2014).

Type locality: syntype localities in various places in the Indian and Pacific Oceans (Silva et al. 1996).


Udotea orientalis, KZN specimens.

 Udotea orientalis, showing concentric growth lines.


References Udotea orientalis

Gepp, A. & Gepp, E.S. (1911). The Codiaceae of the Siboga Expedition including a monograph of Flabellariaea and Udoteae Siboga-Expeditie Monographie LXII. pp. 1-150, 22 pls. Leiden: E.J. Brill.

Guiry, M.D. & Guiry, G.M. 2014. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway.; searched on 14 July 2014.

Silva, P.C., Basson, P.W. & Moe, R.L. (1996). Catalogue of the benthic marine algae of the Indian Ocean. University of California Publications in Botany 79: 1-1259.


Cite this record as:

Anderson RJ, Stegenga H, Bolton JJ. 2016. Seaweeds of the South African South Coast.
World Wide Web electronic publication, University of Cape Town,; Accessed on 02 March 2024.