Electronic Flora of South Australia Family Fact Sheet

FAMILY CLADOPHORACEAE Haeckel

Phylum Chlorophyta – Order Cladophorales

Thallus erect or prostrate, attached or free-living, of free uniseriate filaments, branched or unbranched, with apical and usually few to many intercalary divisions resulting in most genera in cells of more or less similar length (though often basally longer in erect species) but of irregular length in Cladophoropsis; branching when present usually from the upper ends of cells; attaching rhizoids from the lower poles of basal or suprabasal cells. Chloroplasts numerous and densely packed or forming a reticulum, some chloroplasts containing a bilenticular pyrenoid.

Reproduction: Reproduction by biflagellate gametes and from sporophyte by quadriflagellate or biflagellate zoospores; in some species asexual only.

Life history isomorphic.

Taxonomic notes: Species of Cladophoraceae are common on most southern Australian coasts, usually in shallow water or the lower eulittoral. Most are easily recognised as members of this family but the slender, small-celled species of Rhizoclonium may be confused with the uninucleate celled, unbranched, filaments of Ulothrix (which differs in chloroplast structure and is basally attached). Entangled species of Cladophora may be confused with Cladophoropsis, which has relatively few and more irregularly placed cross walls and does not have basal cross walls to the laterals.

References: The Marine Benthic Flora of Southern Australia Part I

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 GENERA OF CLADOPHORACEAE

1. Thallus of unbranched filaments, except for occasional, short, lateral rhizoids in some species

2

1. Thallus branched, occasionally to (usually) much branched

3

2. Filaments slender, less than 60 µm in diameter, with (or occasionally without) short, rhizoidal laterals; loose-lying, forming entangled mats or strands

RHIZOCLONIUM

2. Filaments usually robust, over 70 µm in diameter, either erect with an elongate basal attachment cell or loose-lying without basal cells

CHAETOMORPHA

3. Thallus erect, robust, dendroid, with a row, whorl or cluster of branches which reach similar size from the apex of clavate segments 1–6 cm long and usually over 1 mm broad; annular constrictions present on lower parts of each segment and older segments producing hapteroid cells at their base

APJOHNIA

3. Thallus slender to robust, prostrate to pulvinate or erect and tufted, or globose, with apical and usually intercalary divisions, subapical cells producing lateral cells which do not form whorls on older parts; apical cells less than 400 µm in diameter, older segments less than 1 mm in diameter; hapteroid cells not formed

4

4. Thallus of entangled filaments forming mats or cushions; lateral branches irregularly placed and without a basal cross wall (leaving the lateral and parent cell in open connection); cells of various lengths but mostly long, in most but not all species with a descending rhizoid from the base of the cell above a lateral

CLADOPHOROPSIS

4. Thallus of erect tufts or forming mats or cushions; lateral branches usually regularly placed, in some species irregular, but always with a basal cross wall at or near junction of cells; cells of fairly uniform length (at least at comparable ages), in some species more irregular

5

5. Thallus without hairs, of entangled mats with slender erect filaments or forming erect tufts; cells each of fairly uniform diameter; rhizoids when present not markedly tapering

CLADOPHORA

5. Thallus of prostrate filaments or mats to 10 cm across and 7 mm thick, or globular and up to 12 cm in diameter; cells sometimes with occasional slender hairs; thallus of irregularly branched filaments of short (L/B usually 1–3), irregularly shaped and sized cells, often bulging, with frequent rhizoids each of several cells and tapering markedly from the parent cells

WITTROCKIELLA


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