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Electronic Flora of South Australia Genus Fact Sheet

Genus GYMNOGONGRUS Martius 1833: 27

Phylum Rhodophyta – Class Florideophyceae – Order Gigartinales – Family Phyllophoraceae

Thallus erect, much branched more or less complanately, with a crustose holdfast, branches terete or (usually) compressed, subdichotomous, apices usually rounded. Structure multiaxial, medulla pseudoparenchymatous with medium to large ovoid to angular cells, and a cortex of 2–3 layers of smaller isodiametric cells in anticlinal rows.

Reproduction: Sexual thalli dioecious. Carpogonial branches 2 or 4-celled, supporting cell acting as auxiliary cell with the gonimoblasts growing out through the cortex to form a pustule with surface nemathecia of catenate rows of cruciately divided tetrasporangia, terminated by one to several sterile cells.

Life history biphasic with erect gametophytes and crustose tetrasporophytes, the latter as pustules ("tetrasporoblasts") on the surface of female gametophytes.

Type species: G. griffithsiae (Turner) Martius 1833: 27.

Taxonomic notes: A genus of some 30 species after the transfer of cystocarpic species to Ahnfeltiopsis by Silva & DeCew (1992), Masuda (1993) and herein. Further species are likely to be transferred as life histories are studied. Of the species still assigned to Gymnogongrus, only 5 are known to produce tetrasporoblastic pustules: G. chiton (Howe) Silva, G. crenulatus (Tumer).1. Agardh, G. dilatatus (Turner) J. Agardh, G. griffithsiae (Tumer) Martius, and an undescribed South African species known as G. tetrasporifenis (Anderson & Bolton 1990, p. 383).


ANDERSON, R.J. & BOLTON, J.J. (1990). Reproductive morphology and life histories of southern African Gymnogongrus species (Rhodophyta, Phyllophoraceae). Br. phycol. J. 25, 381–390.

MARTIUS, C.F.P. (1833). Flora Brasiliensis seu enumeratio plantarum, Vol. 1 (1). (Stuttgart & Tubingen.)

MASUDA, M. (1993). Ahnfeltiopsis (Gigartinales, Rhodophyta) in the western Pacific. Jap. J. Phycol. (SOrui) 41, 1–6.

SILVA, P.C. & DECEW, T.C. (1992). Ahnfeltiopsis, a new genus in the Phyllophoraceae (Gigartinales, Rhodophyceae). Phycologia 31, 576–580.

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

Author: J.A. Lewis & 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 terete to slightly compressed, 200–400 (–900) µm broad

G. griffithsiae

1. Branches flattened, 2–4 mm broad

G. crenulatus

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