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Order Colaconematales

Family Colaconemataceae J.T. Harper & G. W. Saunders

Genus Colaconema Batters emend. J.T. Harper & G. W. Saunders

Thalli filamentous, monosiphonous, simple or branched, occasionally discoid and pseudoparenchymatous. In some species erect filaments are very short or virtually absent. Cells with one or more parietal chloroplasts which are discoid or irregular in shape (but never stellate), with or without pyrenoids. Life histories triphasic where known, asexual reproduction by monosporangia. Includes the members of the genus Audouinella dealt with by Stegenga (1985) and Stegenga et al. (1997), but follows the molecular study and re-classification of the Acrochaetiales by Harper & Saunders (2002). Descriptions and line-drawings where relevant are from Stegenga et al. (1997).

Besides the nine species recorded from the south coast, we have one probable record of Colaconema dictyotae (Collins) I.-K.Hwang & H.-S.Kim from Keurboomstrand, but insufficient material for illustrations.

1a.Plants with the exception of reproductive cells completely endozoic or endophytic

2

1b. Plants with all or some vegetative cell filaments emergent

3

2a. Plants growing in sponges

C. spongicola

2b. Plants growing in seaweeds

C. endophyticum

3a. Plants matted; with extensive endophytic part and many multicellular pseudohairs (in Codium spp)

C. interpositum

3b. Plants forming individual tufts or partly endophytic/endozoic; pseudohairs rare or absent

4

4a. Monosporangia dome-shaped, with cup-shaped pedicel

C. daviesii

4b. Monosporangia ovate, cylindrical or sub-cylindrical; pedicel when present not cup-shaped

5

5a. Monosporangia usually at least 20 µm long, at least 12 µm in diameter

6

5b. Monosporangia between 10 and 20 µm long, up to 11 µm in diameter

8

6a. Monosporangia cylindrical/truncate, mainly on proximal cells of laterals

C. codicola

6b. Monosporangia ovate, terminal or inserted laterally on branches

7

7a. Single parietal chloroplast per cell, each with 2-4 pyrenoids

C. dictyotae

7b. Cells with 2-4 (-6) parietal chloroplasts each with central pyrenoid

C. caespitosum

8a. Monosporangia 16.5 – 20 µm long, 9-11 µm in diameter

C. nemalionis

8b. Monosporangia 10-12 µm long, 6-8 µm in diameter

9

9a. Erect filaments up to 2-3 mm tall, 6-8 µm in diameter, monosporangia in terminal or lateral clusters

C. pectinatum

9b. Erect filaments up to 800 µm tall, 10-12 µm in diameter near base, monosporangia in secund series

C. seriatum

 

References genus Colaconema

Harper, J.T. & Saunders, G.W. (2002). A re-classification of the Acrochaetiales based on molecular and morphological data, and establishment of the Colaconematales, ord. nov.. European Journal of Phycology 37: 463-475.

Stegenga, H. (1985). The marine Acrochaetiaceae (Rhodophyta) of southern Africa. South African Journal of Botany 51: 291-330, 25 figs, 1 table.

Stegenga, H., Bolton, J.J. and 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 25 September 2018.