Electronic Flora of South Australia
Electronic Flora of South Australia
Census of SA Plants, Algae & Fungi
Identification tools

Electronic Flora of South Australia Family Fact Sheet


Phylum Rhodophyta – Class Florideophyceae – Order Gigartinales

Thallus erect (or tetrasporophyte crustose), firm, subdichotomously to irregularly branched, sometimes proliferous, branches terete to compressed or flat. Structure multiaxial, pseudoparenchymatous throughout with a medulla of compact ovoid cells and a small-celled cortex, often in anticlinal rows.

Reproduction: Sexual thalli monoecious or dioecious. Carpogonial branches situated in the inner cortex, 2- or 4-celled, directed outwards, procarpic with the supporting cell serving as the auxiliary cell. Carposporophytes discrete or forming a central line along the branches, carposporangia usually in clusters separated by sterile filaments; non-ostiolate. Spermatangia cut off from outer cortical cells.

Tetrasporangia formed in catenate rows in nemathecia or pustules on the surface of, or surrounding, branches, produced from outer cortical cells, cruciately divided.

Life history triphasic with isomorphic or heteromorphic gametophytes and tetrasporophytes, biphasic with tetrasporangia occurring on the female gametophyte, or apomictic.

Taxonomic notes: Silva (1980, p. 86) has pointed out that Phyllophoraceae Nägeli (1847, p. 248) is the correct name for this family, since Tylocarpaceae Kützing (1843, p. 390) is not available as it is based on Tylocarpus which is a superfluous and hence illegitimate name.

A group of 9 genera (Maggs 1990, p. 120) of which 4 occur in southern Australia, held together by their multiaxial pseudoparenchymatous thalli of larger medullary cells with a small-celled cortex, by their procarpic 2- or 4-celled carpogonial branches, and especially by the catenate rows of cruciately divided tetrasporangia formed in superficial nemathecia or pustules.

Ahnfeltia, in which tetrasporangia are zonate in a crustose phase, has now been elevated to its own family and order (Maggs & Pueschel 1989).


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

MAGGS, C.A. & PUESCHEL, C.M. (1989). Morphology and development of Ahnfeltia plicata (Rhodophyta): proposal of Ahnfeltiales ord. nov. J. Phycol. 25, 333–351.

MAGGS, C.A. (1990). Taxonomy of phyllophoroid algae: the implications of life history. Hydrobiologia 204/205, 119–124.

NÄGELI, C. (1847). Die neueren Algensysteme. (Zürich.)

SILVA, P.C. (1980). Names of classes and families of living algae. Regnum vegetabile 103, 1–156.

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

Author: H.B.S. Womersley

Publication: Womersley, H.B.S. (14 January, 1994)
The Marine Benthic Flora of Southern Australia
Rhodophyta. Part IIIA, Bangiophyceae and Florideophyceae (to Gigartinales)
Reproduced with permission from The Marine Benthic Flora of Southern Australia Part IIIA 1994, by H.B.S. Womersley. Australian Biological Resources Study, Canberra. Copyright Commonwealth of Australia.


1. Branches compressed to flat, 2–15 mm broad; carposporophytes forming a central longitudinal line, often interrupted, along the branches; tetrasporophytes isomorphic with scattered tetrasporangial nemathecia


1. Branches terete or compressed, 1–5 mm broad; carposporophytes ovoid, scattered on upper parts of the thallus; tetrasporangia in nemathecia or pustules on branch surfaces of separate tetrasporophytes or on female plants


2. Branches compressed, 2–5 mm broad, with basal stolons and often with proliferations; tetrasporophytes isomorphic with gametophytes, producing tetrasporangial nemathecia in bands on thallus surface


2. Branches terete or compressed, 0.5–1.5 mm broad (2–4 mm broad in Gymnogongrus crenulatus); gametophytes and tetrasporophytes heteromorphic with tetrasporangia in pustules on or around the branches or in free-living crusts 3. Gametophytes erect, terete or compressed; carposporophytes with clusters of carposporangia in a filamentous matrix; tetrasporophytes crustose with tetrasporangia formed in superficial nemathecia


3. Gametophytes erect, usually compressed; gonimoblast filaments growing through the cortex to form pustules with catenate rows of tetrasporangia


Disclaimer Copyright Disclaimer Copyright Email Contact:
State Herbarium of South Australia
Government of South Australia Government of South Australia Government of South Australia Department for Environment and Water