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Electronic Flora of South Australia Genus Fact Sheet

Genus DOXODASYA (Schmitz) Falkenberg 1901: 537.

Phylum Rhodophyta – Family Rhodomelaceae – Tribe Lophothalieae

Thallus erect, radially branched, corticated, branches clothed with rhodoplastic, relatively persistent trichoblasts and in some species with adventitious monosiphonous filaments; holdfast fibrous. Structure monopodial, trichoblasts rhodoplastic, cut off from axial cells close to apices, with 4 pericentral cells developed from axial cells in alternating sequence, remaining clear in transverse section of corticated branches. Trichoblasts simple or with 1–4 branches, dichotomies with or without adherent basal walls. Cells usually uninucleate.

Reproduction: Gametophytes dioecious. Procarps borne on lower cells of trichoblasts, on the last of 5 pericentral cells, developing a sterile cell group and a 4-celled carpogonial branch. Carposporophyte with a basal fusion cell and branched gonimoblast filaments with clavate terminal carposporangia. Cystocarps globose to urceolate, with or without a neck, pericarp ostiolate, corticated or not. Spermatangial organs developed on branches of trichoblasts.

Tetrasporangia produced in lesser branches, sometimes stichidioid, usually with normal trichoblasts, in decussate pairs with 2–3 cover cells.

Type species: D. bolbochaete (Harvey) Falkenberg 1901: 538, pl. 13 figs 21, 22.

Taxonomic notes: Doxodasya was first described by Schmitz (1893, p. 220) as a subgenus of Lophothalia, and elevated to a genus by Falkenberg.

The genus now comprises 4 species, 3 recognised by Schmitz (1893, p. 220) and Dasya hirta J. Agardh here transferred to Doxodasya. Doxodasya lenormandiana and D. hirta are both much less common species than the other two; they agree with Doxodasya in essential features but differ in having more robust, branched, trichoblasts with adherent basal walls to cells above the dichotomies (as in Dasyaceae), and D. lenormandiana is distinctive in having very slender, branched filaments on cells of the trichoblasts.


FALKENBERG, P. (1901). Die Rhodomelaceen des Golfes von Neapel und der angrenzenden Meeres-abschnitte. Fauna und Flora des Golfes von Neapel. Monogr. 26. (Friedländer: Berlin.)

SCHMITZ, F. (1893). Die gattung Lophothalia, J. Ag. Ber. Deutsch. Bot. Ges. 11, 212–232.

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

Author: H.B.S. Womersley & M.J. Parsons

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. Trichoblasts mostly simple, occasionally basally branched, 12–25 µm in diameter with mid cells L/D 3–8; branch walls not adherent at dichotomies where branched


1. Trichoblasts with 1–4 branches, lower cells 20–80 µm in diameter and L/D 1–2.5; branch walls adherent at dichotomies


2. Branches bearing discrete, tufted, short shoots with trichoblasts, adventitious filaments absent

D. bolbochaete

2. Branches densely covered with short shoots and adventitious filaments

D. lanuginosa

3. Trichoblasts rigid, lower cells 60–80 µm in diameter, terminal cells mucronate, some cells bearing branched slender filaments 5–8 µm in diameter, adventitious filaments absent

D. lenormandiana

3. Trichoblasts rigid below, with long lax ends, lower cells 20–30 µm in diameter, terminal cells pointed; adventitious filaments frequent on lower branches

D. hirta

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