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Order Ceramiales

Family Dasyaceae

Dasya C. Agardh

Thallus erect, bottlebrush-like or bushy. Development sympodial, with irregular, opposite or alternate branching. Indeterminate axes producing determinate monosiphonous pseudolaterals from each polysiphonous segment. Spermatangia similarly borne in heads on pseudolaterals. Carposporophytes, where known, enclosed in a sterile pericarp. This genus on the south coast needs taxonomic attention: we appear to have at least three undescribed species.

Key to species

 

1a. Branching angle in distal dichotomies about 90o; ultimate ramuli relatively short, straight

D. echinata

1b. Branching angle in distal dichotomies narrow or at least less than 60o; ultimate ramuli relatively long

2

2a. Thallus with extensive, fully corticated creeping axes; main erect axes incompletely corticated

Dasya sp III

2b. Thallus mainly erect with no or short creeping axes; main erect axes fully corticated

3

3a. Main axes prominent and thickly corticated, up to 1 mm in diameter, thickly clothed with pseudolaterals

Dasya scoparia

3b. Main axes corticated but less than 250 µm in diameter

4

4a. Thallus with short creeping system bearing more than one erect axis; pseudolaterals branched up to 5 times; tetrasporangial stichidia ca 800 µm X 125 µm

Dasya sp II

4b. Thallus erect with no creeping system; pseudolaterals branched 2-3 times; tetrasporangial stichidia ca 350 µm X 100 µm

Dasya sp I

 

 

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 24 September 2018.