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Order Ceramiales

Family Dasyaceae

Heterosiphonia Montagne

Thallus erect or partly prostrate, feather-like or bushy, dorsiventrally organised; branching sympodial, distichous pseudolaterals arising at intervals of every two or more segments, branching irregular, subdichotomous or alternate. Axial cell surrounded by 4-12 periaxials; mature axes with or without rhizoidal cortication. Plants dioecious, carposporophytes with prominent corticated pericarps, ostiolate; spermatangia in whorls in linear to lanceolate stichidia.

In addition to the three species below (descriptions from Stegenga et al. 1997), we recorded an entity similar to H. arenaria but with a thicker main axis and some cortication (see illustrations under H. arenaria), which may represent an undescribed species.

Key to species

 

1a. Segments of main axes with 4 pericentral cells

H. crispa

1b. Segments of main axes with more than 4 pericentral cells

2

2a. Pseudolaterals arising at intervals of every second segment

H. dubia

2b. Pseudolaterals arising at intervals of every third to fourth segment

H. arenaria

 

References Heterosiphonia

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, http://southafrseaweeds.uct.ac.za; Accessed on 20 November 2018.