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Order Ceramiales

 

Family Rhodomelaceae

 

Chondria C. Agardh

 

Thallus branched, cylindrical to flattened, variable in size. Branching radial sometimes becoming secondarily distichous, branches usually narrowing at both ends, apices either pointed or sunken in a terminal pit. Holdfast a basal crust or prostrate stoloniferous branches. Structure polysiphonous, with a distinct central and 5 distinct pericentral cells. Cortication is by division of the pericentrals, producing a cortex with an inner layer of large pseudoparenchymatous cells and an outer layer (epidermis) of small, pigmented cells. Trichoblasts arranged spirally, usually highly branched.

 

Chondria species are found in most regions of the world, from the subantarctic to the tropics: 85 species and sub-specific taxa are currently recognised (MD Guiry in Guiry & Guiry 2016).

 

Although several species are recorded from the South African south coast, several more are present, and a molecular/morphological study of our species is overdue. Small Chondria species are common in algal turfs on the south coast, but we do not know how many species may be present: thorough collections and descriptions are required. Here we describe only one of these, a distinctive, larger entity, as Chondria sp. Indet.

 

Key to the species

 

1a. Apices of axes with terminal pits, often containing tufts of trichoblasts

2

1b. Apices of axes pointed, without terminal pits but sometimes bearing trichoblasts

3

2a. Plants to 10 cm tall; axes stiffish, with spots/areas of green to turquoise iridescence; branches sparse, irregular

Chondria sp. Indet.

2b. Plants to 10 cm tall; axes soft, without iridescence; branches fairly profuse

C. dasyphylla

3a. Axes stiffish, uprights to ca. 2 cm tall; main axis to 1 mm diameter; with radially-arranged branches up to 5 mm long: apices acute

C. armata

3b. Axes stiffish to lax, uprights to 20 (-30) cm tall; main axis to 3 mm diameter; branches several to 10 cm long

C. capensis

 

References Chondria

Guiry M.D. in Guiry, M.D. & Guiry, G.M. 2016. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org; searched on 31 May 2016.

 

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 15 November 2018.