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Order Ceramiales

Family Wrangeliaceae

Pleonosporium harveyanum (J. Agardh) De Toni 1903: 1309

Plants up to 5 cm tall, bushy, with several erect axes; older axes with a loose rhizoidal cortication. Branching alternate, in the apical sections of the plant generally complanate. The ultimate branchlets (apart from reproductive organs) long and unbranched, near the apices strongly incurved. Main axes up to 200 µm broad (without cortication), ultimate cells 15 µm broad, the cells 2-3 times longer than broad.

Polysporangia sessile on a row of basal cells of the laterals, almost round, measuring ca. 110 µm in diameter, producing ca. 32-64 spores. Spermatangial stands adaxial on a number of cells of the ultimate branchlets, cylindrical with a ca. six-celled central axis, measuring ca. 140 x 50 µm at maturity.Female structures not seen in south coast material, for a description see Stegenga (1986).

Collections, ecology and regional distribution

Recorded along the whole west coast (Stegenga et al. 1997) and south coasts, to Port Shepstone in KwaZulu-Natal (1-49). Epilithic, occasionally on other algae or Pyura. Although primarily a West Coast species, it is not rare on the south coast, but it seldom grows longer than 2 cm.

World distribution: southern African endemic, also recorded from Namibia (Rull Lluch 2002) and Mozambique (Silva et al. 1996).

Type locality: Cape of Good Hope, South Africa (Silva et al. 1996).


Pleonosporium harveyanum. Detail of thallus with polysporangia. Reproduced from Stegenga et al. (1997).

Pleonosporium harveyanum. Thallus apex with polysporangia (Haga Haga, stained slide).

Pleonosporium harveyanum. Detail of polysporangia (Haga Haga, stained slide).

Pleonosporium harveyanum. Spermatangial stands (Haga Haga, stained slide).


References Pleonosporium harveyanum

De Toni, G.B. 1903. Sylloge algarum omnium hucusque cognitarum. Vol. IV. Florideae. Sectio III. pp. [i], frontispiece, [iii-v], 775, 775 bis, 776, 777 bis, 777-1521 + 1523-1525. Patavii [Padua]: Sumptibus auctoris.

Rull Lluch, J. 2002. Marine benthic algae of Namibia. Scientia Marina 66 (Supplement 3): 258 pp.

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.

Stegenga, H. 1986. The Ceramiaceae (excl. Ceramium) (Rhodophyta) of the South West Cape Province, South Africa. Bibliotheca Phycologica 74: 149 pp.

Stegenga, H., Bolton, J.J. & R. J. Anderson. 1997. Seaweeds of the South African west coast. Contributions from the Bolus Herbarium 18: 655 pp.


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 19 April 2024.