Electronic Flora of South Australia Species Fact Sheet

Cladophora coelothrix Kützing 1843: 272.

Phylum Chlorophyta – Order Cladophorales – Family Cladophoraceae

Selected citations: van den Hoek 1963: 40, figs 55–78; 1982: 47, figs 11–29.

Synonym

Cl. repens (J. Agardh) Harvey 1849: pl. 236. Womersley 1956: 359.

Thallus (Fig. 60C) medium to dark green, drying brownish, forming dense turfs or cushions to several cm across and to 4 cm high, composed of a basal tangle of branched, often curved, stolon-like filaments giving rise to ascending, more or less erect, branch-systems (Fig. 61C).

Growth largely by divisions of conspicuous apical cells, but intercalary cells may divide into shorter cells; feebly to distinctly acropetal at the apices, densely and irregularly branched with many cells (especially lower ones but often also those near the apices) producing a descending rhizoid from their basal poles (Fig. 61C,D), and which attach to the substrate or other filaments with a terminal coralloid holdfast; lateral branches mostly wide-angled (45° or more) arising singly (occasionally two) at or just below a cross wall, with the new wall remaining steeply inclined to the parent cell.

Apical cells 60–140 µm in diameter, L/B 3–16, cylindrical with rounded ends; mid and lower thallus cells 70–220 µm in diameter, L/B 2–11; ratio of lower cell to apical cell diameters (0.6–) 1–1.5 (–2.5); cell walls thin in younger cells (2–4 µm), mostly 4–8 µm thick below and up to 20 µm thick in old cells.

Reproduction: Reproduction by zooids developing in normal vegetative cells at or near apices of outer filaments of the cushions.

Type from Livorno, Italy (Meneghini); in L (937, 278 ... 392).

Selected specimens: Point Sinclair, S. Aust., upper sublittoral, in gulch, shaded ( Womersley, 9.ii.1954; ADU, A19606). Wittelbee Point, near Ceduna, S. Aust., low eulittoral pool ( Womersley, 21.i.1951; ADU, A15166). Venus Bay, S. Aust., upper sublittoral reef pools (Womersley, 17.i.1951; ADU, A15172). Wanna, S. Aust., low eulittoral (Womersley, 14.ii.1959; ADU, A22470). Louth Bay, S. Aust., upper sublittoral (Womersley, 5.i.1951; ADU, A15182). Pennington Bay, Kangaroo I., S. Aust., drift (Womersley, 13.iv.1947; ADU, A4498).


Distribution map based
on current data relating to
specimens held in the
State Herbarium of SA

Distribution: Warm temperate to tropical Atlantic coasts of Europe, Africa and America; probably widespread in tropical and warm temperate waters.

In southern Australia, from Fremantle, W. Aust. around southern Australia (not Tasmania) to Moreton Bay, Qld., common in shaded areas or pools near low tide level on rough-water coasts but extending into sheltered areas.

Taxonomic notes: Cl. coelothrix is distinguished by its habit, long cylindrical apical cells, irregular branching, dimensions, and by the presence of rhizoids from the basal poles of many of the cells. In the eastern part of its range, plants are coarser with thicker filaments (mostly 140–220 µm) than in the western part where softer plants have filaments mostly 80–100 µm in diameter.

References:

HARVEY, W.H. (1849). Phycologia Britannica. Plates 217–252 (Reeve: London.)

KÜTZING, F.T. (1843). Phycologia generalis. (Leipzig.)

VAN DEN HOEK, C. (1963). Revision of the European species of Cladophora. (Brill: Leiden.)

VAN DEN HOEK, C. (1982). A taxonomic revision of the American species of Cladophora (Chlorophyceae) in the North Atlantic Ocean and their geographic distribution. Verh. k. Ned. Akad. Wet. Afd. Natuurkd. Tweede Reeks, Part 78.

WOMERSLEY, H.B.S. (1956). A critical survey of the marine algae of southern Australia. I. Chlorophyta. Aust. J. mar. freshw. Res. 7, 343–383.

The Marine Benthic Flora of Southern Australia Part I complete list of references.

Author: C. van den Hoek and H.B.S. Womersley.

Publication: Womersley, H.B.S. (31 May, 1984)
The Marine Benthic Flora of Southern Australia
Part I
©Board of the Botanic Gardens and State Herbarium, Government of South Australia


Illustration in Womersley Part I, 1984: FIGS 60C, 61C,D.

Figure 61 image

Figure 61   enlarge

Fig. 61. A,B. Cladophora aegagropiloidea (Type, ADU, Al2607). A. Upper branch system. A'. Part of thallus showing reversion of polarity. B. Lower thallus. C,D. Cladophora coelothrix (ADU, A22470). Branch systems with rhizoids. E–I. Cladophora subsimplex (E–H, ADU, A30024; I, ADU, A52662). E. Branching pattern. F. Upper branch system. G. Apical cell. H. Lower branches with rhizoids. I. Fertile upper branches.


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