Electronic Flora of South Australia Species Fact Sheet

Rhabdonia coccinea (Harvey) Hooker & Harvey 1847: 408.

Phylum Rhodophyta – Class Florideophyceae – Order Gigartinales – Family Areschougiaceae

Selected citations: J. Agardh 1852: 354; 1876: 591. Harvey 1858: pl. 54; 1860a: 321. Kützing 1849: 723; 1866: 26, pl. 73c, d. Kylin 1932: 36; 1956: 289, fig. 220A. Lucas & Perrin 1947: 171, fig. 42A–F. Min-Thein & Womersley 1976: 39,.figs 13, 14, 54.

Synonyms

Chrysymenia coccinea Harvey 1844: 448.

Rhabdonia harveyi Sonder 1853: 681 (in part).

Rhabdonia dendroides Harvey 1860b: pl. 152. J. Agardh 1872: 38; 1876: 591. Kylin 1932: 36, fig. 7H. Lucas & Perrin 1947: 172.

Thallus (Fig. 113A) medium to dark red, erect, 5–25 cm high, much branched irregularly with terete, linear, gently tapering branches 200–400 µm in diameter above, 0.5–1.5 mm in central parts, and in dendroid specimens 2–3 mm thick in lower axes. Holdfast discoid, 2–8 mm across with one to several axes and becoming stoloniferous from their bases; epilithic. Structure uniaxial (Figs 114A, B), with periaxial initials single per axial cell and on three radii, developing rhizoids and forming a laxly to moderately filamentous medulla (Fig. 114C) in which the original axial filament becomes inconspicuous; occasional filaments become thickened (Fig. 114B) and filled with yellow refractive material; cortex at first 2–5 cells thick (later 5–8 cells thick), inner cells ovoid, multinucleate, 20–80 µm in diameter, outer cells isodiametric, (6–) 10–15 µm in diameter; bases of older axes thickened from a cortical meristem, becoming perennial with new apical growth. Rhodoplasts discoid to elongate, many per cell.

Reproduction: Sexual thalli monoecious; non-procarpic. Carpogonial branches (Fig. 114D) 3 (–4)-celled, borne on inner cortical cells, directed inwards with a reflexed trichogyne, rarely with a sterile cell on the basal cell. Connecting filament single, nonseptate, unbranched, uniting with the auxiliary (inner cortical) cell in a darkly staining complex (Fig. 114D) (probably so before connection). Gonimoblast initial first inwards, later with a prominent fusion cell (connected to an enlarged medullary filament) with radial gonimoblasts (Fig. 114E) producing short chains (the terminal one mature) of ovoid carposporangia 50–90 µm in diameter. Cystocarps swelling one side of lesser branches, without filamentous enveloping tissue but with a pericarp of thickened cortex, ostiolate. Spermatangia (Fig. 114F) scattered near branch apices, with surface cortical cells cutting off 3–6 initials, each of which produces 2–3 ovoid spermatangia, 2–3 µm in diameter.

Tetrasporangia (Fig. 114G) scattered in the cortex of younger branches, cut off laterally, ovoid, 80–100 nm long and 60–80 µm in diameter, zonately divided.

Type from Georgetown, Tas. (Gunn 1301); holotype in BM.

Selected specimens: Champion Bay, W. Aust. (MEL, 44569). Esperance, W. Aust., drift (Firman, Dec. 1952; AD, A18950). Point Malcolm, Israelite Bay, W. Aust., drift (Willis, 28.xi.1950; AD, A15903). The Hotspot, near Flinders I., S. Aust., 25 m deep (Branden, 23.i.1991; AD, A61214). Between Hopkins and Thistle Is, S. Aust., 6–9 m deep (Baldock, 1.i.1964; AD, A27126). Northern Spencer Gulf, S. Aust., 11 m deep (Shepherd, 4.ix.1973; AD, A44106). 3 km SE of Marion Light, Gulf St Vincent, S. Aust., 24 m deep (Shepherd, 5.ii.1969; AD, A33886). Aldinga, S. Aust., drift (Womersley, 31.xii.1967; AD, A32200). Cape Jervis, S. Aust., 10–12 m deep (Shepherd, 29.xi.1983; AD, A54604). Seal Bay, Kangaroo I., S. Aust., shaded reef pool (Womersley, 29.x.1966; AD, A31113). Kirk Point, Port Phillip, Vic., drift (Min-Thein, 11.viii.1970; AD, A36033). Wa]kerville, Vic., drift (Sinkora A2068, 26.ii.1975; AD, A48544). Snowy R. mouth, Vic. (Mueller, Feb. 1855; MEL, 44557). Satellite I., D'Entrecasteaux Ch., Tas., 10 m deep (Shepherd, 18.ii.1972; AD, A41693).


Distribution map based
on current data relating to
specimens held in the
State Herbarium of SA

Distribution: Champion Bay, W. Aust., to the Snowy R. mouth, Vic., and around Tasmania.

Taxonomic notes: R. coccinea is a deeper water species on rough-water coasts or with strong tidal currents, distinguished by its form and the presence of elongate, refractive, inclusions in young branches.

References:

AGARDH, J.G. (1852). Species Genera et Ordines Algarum. Vol. 2, Part 2, pp. 337–720. (Gleerup: Lund.)

AGARDH, J.G. (1872). Bidrag till Florideernes Systematik. Acta Univ. hind. 8, 1–60.

AGARDH, J.G. (1876). Species Genera et Ordines Algarum. Vol. 3, Part 1 - Epicrisis systematis Floridearum, pp. i-vii, 1–724. (Weigel: Leipzig.)

HARVEY, W.H. (1844). Algae of Tasmania. Lond. J. Bot. 3, 428–454.

HARVEY, W.H. (1858). Phycologia Australica. Vol. 1, Plates 1–60. (Reeve: London.)

HARVEY, W.H. (1860a). Algae. In Hooker, J.D., The Botany of the Antarctic Voyage. 111. Flora Tasmaniae. Vol. II, pp. 321–343, Plates 185–196.

HARVEY, W.H. (1860b). Phycologia Australica. Vol. 3, Plates 121–180. (Reeve: London.)

HOOKER, J.D. & HARVEY, W.H. (1847). Algae Tasmanicae. Lond. J. Bot. 6, 397–417.

KÜTZING, F.T. (1849). Species Algarum. (Leipzig.)

KÜTZING, F.T. (1866). Tabulae Phycologicae. Vol. 16. (Nordhausen.)

KYLIN, H. (1932). Die Florideenordnung Gigartinales. Lunds Univ. Årsskr. N.F. Avd. 2, 28 (8), 1–88, Plates 1–28.

KYLIN, H. (1956). Die Gattungen der Rhodophyceen. (Gleerups: Lund.)

LUCAS, A.H.S. & PERRIN, F. (1947). The Seaweeds of South Australia. Part 2. The Red Seaweeds. (Govt Printer: Adelaide.)

MIN-THEIN, U. & WOMERSLEY, H.B.S. (1976). Studies on southern Australian taxa of Solieriaceae, Rhabdoniaceae and Rhodophyllidaceae (Rhodophyta). Aust. J. Bot. 24, 1–166.

SONDER, O.W. (1853). Plantae Muellerianae. Algae. Linnaea 25, 657–709.

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.


Illustrations in Womersley Part IIIA, 1994: FIGS 113A, 114 A–G.

Figure 113 image

Figure 113   enlarge

Fig. 113. A. Rhabdonia coccinea (AD, A61214). Habit. B. Rhabdonia verticillata (AD, A41031). Habit. C–E. Rhabdonia clavigera. (C, AD, A31637; D, E, AD, A57594). C. Habit. D. Transverse section of branch with a carposporophyte with central fusion cell and radiating gonimoblast filaments with terminal carposporangia. E. Transverse section of cortex with tetrasporangia.

Figure 114 image

Figure 114   enlarge

Fig. 114. A–G. Rhabdonia coccinea (A–E, AD, A33886; F, AD, A27126; G, AD, A32200). A. Longitudinal view of branch apex; axial cells stippled, part of a refractive filament shown below. B. Longitudinal section of young branch showing axial filament, medullary filaments, cortex and parts of a refractive filament. C. Transverse section of an older branch. D. Longitudinal section with four carpogonial branches and an auxiliary cell complex. E. Longitudinal section of carposporophyte with elongate fusion cell, radiating gonimoblast filaments and displaced carposporangia. F. Longitudinal section of cortex with spermatangia and a carpogonial branch. G. Section of cortex with immature and mature tetrasporangia, and a hair. H–M. Rhabdonia verticillata (H, I, M, AD, A21244; J, K, AD, A16405; L, AD, A35150). H. Longitudinal section of part of a segment, with axial filament, periaxial cells of medulla, and descending rhizoids. I. Transverse section of older branch with axial core and medulla largely filled with rhizoids. J. Section of cortex with a fertilized carpogonial branch producing a connecting filament. K. Longitudinal section with a carposporophyte surrounded by a lax involucre and with four germinating carposporangia. L. Section of cortex with spermatangia. M. Section of cortex with immature and mature tetrasporangia. [A–M after Min-Thein & Womersley 1976.]


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