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

Electronic Flora of South Australia Genus Fact Sheet

Genus PLATYSIPHONIA Børgesen 1931b: 8.

Phylum Rhodophyta – Family Sarcomeniaceae

Thallus much branched, decomposing readily, with compressed branches, usually heavily corticated on lower terete axes; holdfast branched or prostrate with rhizoids. Structure. Apical cells hemispherical, axial cells cutting off 4 periaxial cells in alternating sequence, the lateral pericentral cells each forming 2 flanking cells which do not divide further in vegetative parts. Cortication slight in some species to heavy in others. Lateral branches endogenous from central cells. Cells uni to multinucleate.

Reproduction: Gametophytes dioecious. Procarps borne on the adaxial pericentral cells, which cut off a sterile cell, a 4-celled carpogonial branch, then a second sterile cell. Carposporophyte with an erect, basal fusion cell and much branched gonimoblast filaments bearing terminal carposporangia, often replaced from below. Cystocarps ovoid to urceolate; pericarp ostiolate, of erect filaments with each cell cutting off 2 outer pericentral cells, becoming corticated below in some species. Spermatangial blades with sterile bases and tips and sterile transverse pericentral cells and flanking cells.

Tetrasporangial stichidia formed from lateral branches with the lateral pericentral cells each cutting off a tetrasporangium and cover cells on both sides of the blade, with the flanking cells in most (but not all) species each dividing into 2 and becoming curved around the edge of the stichidium.

Type species: P. miniata (C. Agardh) Børgesen 1931 b: 8 [= P. delicata (Clemente) Cremades in Cremades & Perez-Cirera 1990: 492].

Taxonomic notes: A genus of some 10 species. As well as the 3 southern Australian species described below, the heavily corticated and tendril bearing P. hypneoides (Harvey) Womersley & Shepley (1959, p. 209) occurs on the Western Australian coast from Rottnest I. northwards, P. marginalis Wynne, Millar & Kraft (1984, p. 273) occurs on the eastern Australian and Western Australian coasts (Rottnest I. northwards), and P. intermedia (Grunow) Wynne (1983, p. 446) from Western Australia; the latter 2 species have stichidia in which the flanking cells remain undivided.


BØRGESEN, F. (1931b). Sur Platysiphonia nov. gen. et sur les organes mâles et femelles du Platysiphonia miniata (Ag.) nov. comb. (Sarcomenia miniata (Ag.) J.Ag.) Recueil Tray. Crypt. ded. Louis Mangin, pp. 21–29.

CREMADES, J. & PÉREZ-CIRERA, J.L. (1990). Nuevas combinaciones de algas bentónicas marinas, como resultado del estudio del herbario de Simón de Rojas Clemente y Rubio (1777–1827). Anales Jardin Bot. Madrid 47, 489–492.

WOMERSLEY, H.B.S. & SHEPLEY, E.A. (1959). Studies on the Sarcomenia group of the Rhodophyta. Aust. J. Bot. 7, 168–223.

WYNNE, M.J. (1983). The current status of genera in the Delesseriaceae (Rhodophyta). Bot. Marina 26, 437–450.

WYNNE, M.J., MILLAR, A.J.K. & KRAFT, G.T. (1984). Platysiphonia marginalis sp. nov. (Delesseriaceae), a new red alga from eastern Australia. Phycologia 23, 273–279.

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

Publication: Womersley, H.B.S. (24 February, 2003)
The Marine Benthic Flora of Southern Australia
Rhodophyta. Part IIID. Ceramiales – Delesseriaceae, Sarcomeniaceae, Rhodomelaceae
Reproduced with permission from The Marine Benthic Flora of Southern Australia Part IIID 2003, by H.B.S. Womersley. Australian Biological Resources Study, Canberra. Copyright Commonwealth of Australia.


1. Thallus 0.5–1.5 (–3) cm high, not or slightly basally corticate

P. delicata

1. Thallus 6–40 cm high, heavily corticate below


2. Thallus slender, branches corticate only near their base

P. mutabilis

2. Thallus robust, axes 1–2 mm in diameter below. usually corticate from close to apices

P. victoriae

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