Seaweeds of the South African South Coast
Order Ceramiales
Family Spyridiaceae
Spyridia Harvey
Thalli erect, with a clear distinction between indeterminate and determinate branches. Axial cells of indeterminate branches each cutting off a ring of periaxial (=nodal) cells; periaxial cells each cutting off two (internodal) cells in basipetal direction, the latter making a connection with the periaxial cells of the segment below. Cortication of (young) segments thus consisting of two transverse bands of cells of slightly different size and shape. Further cortication in older segments by development of rhizoidal cells. Cells of the determinate laterals each with a ring of nodal cells, with or without further development of cortication, but never in the manner of the main axes. Tetrasporangia on the nodes of the determinate branches, exserted, tetrahedrally divided. Spermatangia covering several segments in the proximal part of determinate laterals. Procarps and carposporophytes on short determinate laterals.
A genus of warm temperate seas, with 15 species currently recognised (Guiry & Guiry 2015), of which five are found on the south coast.
Key to the species
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1a. Segments usually with two determinate laterals |
Spyridia plumosa |
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1b. Segments with one determinate lateral |
2 |
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2a. Plants rather lax, with a single straight terminal spine on the determinate laterals |
Spyridia filamentosa |
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2b. Plants sturdy, with two or more spines on the determinate laterals, in part recurved |
3 |
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3a. Determinate laterals completely corticated |
Spyridia cupressina |
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3b. Determinate laterals not completely corticated, or at least the separate cortical bands clearly visible |
4 |
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4a. Determinate laterals usually with four terminal recurved spines |
Spyridia horridula |
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4b. Determinate laterals with a terminal straight and 1-4 subterminal recurved spines |
Spyridia hypnoides |
References Spyridia
Guiry, M.D. & Guiry, G.M. 2015. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org; searched on 11 December 2015.
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 19 December 2024.