Electronic Flora of South Australia Genus Fact Sheet

Genus CLADOPHOROPSIS Boergesen 1905: 288.

Phylum Chlorophyta – Order Cladophorales – Family Cladophoraceae

Selected citations: Papenfuss 1950: 208.

Thallus filamentous, irregularly branched, forming dense mats, cushions or tufts of entangled filaments, often with emergent, erect filaments above; usually with the lower filaments and in some species with nearly all filaments producing a descending rhizoid from the basal pole of cells, below which a lateral occurs in open connection (no basal cross wall) with the lower cell. Cells of very variable length, shortest where laterals are clustered, and very long above; chloroplast parietal, reticulate, with numerous pyrenoids; numerous nuclei per cell.

Reproduction: Reproduction unknown.

Type species: C. membranacea (C. Agardh) Boergesen 1905: 288, figs 8–13.

Taxonomic notes: A genus of some 20 species, much in need of monographic treatment on a world basis. Two species occur in southern Australia, and C. membranacea also occurs on the N.S.W. and Queensland coasts.

Cladophoropsis is similar to species of Cladophora Section Repentes (especially C. coelothrix) but differs in that cross walls are not present at the base of lateral branches, so that the branch is in open connection with the parent cell. In most species of Cladophoropsis, a descending rhizoid develops from the basal pole of the upper cell, just above the cross wall. The cells in Cladophoropsis are usually quite irregular in length, with some up to a few times as long as broad where laterals are clustered, but others many times longer than broad. In some species of section Repentes of Cladophora, the basal wall of laterals may be delayed in its formation, and rhizoids are usually present from the basal pole of cells at the base of the thallus, but Cladophoropsis appears to be satisfactorily separated from Cladophora at a generic level even though closely related.

Cladophoropsis was first placed in the Cladophoraceae by Boergesen, but later (Boergesen 1913, p. 42) transferred to the Valoniaceae. Boergesen considered that the cells were formed by segregative division as in Siphonocladus, but this has not been convincingly demonstrated and van den Hoek (1982, p. 33) considers that if segregative division does occur in Cladophoropsis then it is not the rule. However, formation of cross walls by ingrowth from the periphery (as normal for Cladophora) has also not been documented in Cladophoropsis.

It seems best to follow van den Hoek in regarding Cladophoropsis as a close relation of Cladophora.

References:

BOERGESEN, F. (1905). Contributions à la connaissance du genre Siphonocladus Schmitz. K. Dan. Vidensk. Selsk. Forh. 1905(3), 259–291.

BOERGESEN, F. (1913). The marine algae of the Danish West Indies. Vol. I. Part I. Chlorophyceae. Dansk. bot. Ark. 1(4), 1–160, map.

PAPENFUSS, G.F. (1950). On the identity of Spongocladia and Cladophoropsis. Pac. Sci. 4, 208–213.

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.

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

Author: 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

KEY TO SPECIES OF CLADOPHOROPSIS

1. Thallus forming dense, entangled mats to 1 cm thick; filaments 240–370 µm in diameter with a rhizoid arising from the basal pole of most cells immediately above a lateral

C. herpestica

1. Thallus forming loose, basally entangled masses 2–7 cm thick, with erect filaments above; filaments 500–700 µm in diameter below and often near their tips, slenderer (170–350 µm in diameter) in their lower and mid parts, without rhizoids associated with each branching

C. magna


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