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Electronic Flora of South Australia Genus Fact Sheet

Genus PHYCODRYS Kützing 1843: 444

Phylum Rhodophyta – Family Delesseriaceae

Thallus erect to decumbent, complanately branched with flat primary blades bearing lateral blades marginally, borne on slender pedicels, monostromatic apart from veins; all blades with a midrib and paired lateral veins (often faint); holdfast discoid, base often stoloniferous. Structure. Apical cell segmenting to give an axial filament and 2 lateral and 2 transverse pericentral cells, the lateral cells forming second-order rows which reach the thallus margin with their cells cutting off third-order cells or rows irregularly and mainly abaxially which fill up the spaces between the second-order rows; transverse intercalary divisions occur in the axial cells, then separating the second-order rows. Margin of blades with short dentations, those terminating second-order rows sometimes developing into lateral blades. Midrib becoming heavily corticated, second-order rows (and adjacent primary cells) becoming lightly corticated.

Reproduction: Gametophytes dioecious. Procarps scattered on monostromatic blades, on opposite sides or not, with a 4-celled carpogonial branch and 2 sterile groups; carposporophytes with a basal fusion cell and branched gonimoblast with terminal chains of carposporangia. Cystocarps swollen on one or both sides of blades, ostiolate, with a pericarp 3–8 cells thick of anticlinal cell rows. Spermatangial sod on both sides of blades between midrib and margins, with a layer of cortical cells on both sides and each cell producing 2–4 spermatangia.

Tetrasporangial sod on blades between midrib and lateral veins, with tetrasporangia in 2 layers, produced laterally from inner cortical cells and covered by a layer of outer cortical cells.

Type species: P. sinuosa (Goodenough & Woodward) Kützing (1843: 444) = P. rubens (Linnaeus) Batters. See Kylin 1923: 64, figs 43–51; Maggs & Hommersand 1993: 215, fig. 68.

Taxonomic notes: A genus of 6 or 7 species, of which P. australasica is the only Australian species.


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

KYLIN, H. (1923). Studien über die Entwicklungsgeschichte der Florideen. K. Svenska Vetensk Akad Handl. 63, 1–139.

MAGGS, C.A. & HOMMERSAND, M.H. (1993). Seaweeds of the British Isles. Vol. 1. Rhodophyta. Part 3A, Ceramiales. (HMSO: London.)

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

Author: H. B. S. Womersley

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.

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