Electronic Flora of South Australia Family Fact Sheet
Thallus filamentous, branched or unbranched, with filaments free or laterally attached forming a complanate net, with fairly regularly placed cross walls separating multinucleate cells; cell division apical or intercalary, cross walls formed by ingrowth from the periphery, independent of nuclear divisions; chloroplasts numerous, parietal, densely packed or united into a reticulum, individual chloroplasts discoid to lenticular, many with a bilenticular pyrenoid; cell wall of crossed microfibrils of cellulose I.
Life history isomorphic, the gametophyte producing biflagellate isogametes (rarely anisogametes) and the sporophyte quadriflagellate zoo(meio)spores or biflagellate zoo(mito)spores; or by parthenogametes.
Taxonomic notes: This order is marked by their large (except Rhizoclonium) but fairly evenly sized cells (in contrast to some Siphonocladales) with each cell containing a few (in Rhizoclonium) to many (Cladophora, Chaetomorpha) nuclei. In attached species such as those of Cladophora and Chaetomorpha, the basal cell(s) are often considerably longer than upper cells, and length of cells above the base, or along loose-lying filaments, can vary depending on when cell division has occurred.
In the family Anadyomenaceae, characterised by net formation, the cells are usually relatively small, containing only a few nuclei.
References: The Marine Benthic Flora of Southern Australia Part I
Womersley, H.B.S. (31 May, 1984)
The Marine Benthic Flora of Southern Australia
©Board of the Botanic Gardens and State Herbarium, Government of South Australia
KEY TO FAMILIES OF CLADOPHORALES
1. Thallus of unbranched or branched filaments, not laterally united to form a net
1. Thallus of filaments united laterally to form a net lying largely in one plane
State Herbarium of South Australia