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Melanthalia concinna J. Agardh 1876: 404.

Phylum Rhodophyta – Class Florideophyceae – Order Gracilariales – Family Gracilariaceae

Selected citations: De Toni 1900b: 421. Chapman 1979: 312, pl. 117(?). Kylin 1932: 58. Lucas 1929b: 49. May 1965: 391(?). Reinbold 1897: 51. Sonder 1881: 22. Tisdall 1898: 508. Womersley 1950: 169.

Thallus (Fig. 11A) dark red-brown, 10–30 cm high, subdichotomously and complanately branched especially in upper parts, mostly at intervals of 5–20 mm, branches terete (Fig. 11B) to slightly compressed, linear, 0.3–0.7 (–1.0) mm broad, only slightly thicker below, branch apices with a thickened cap and 0.3–0.6 mm broad just below apex. Holdfast discoid, 2–10 mm across, bearing few to numerous stipes; epilithic. Structure multiaxial, with rapid transition (Fig. 11C) from smaller cap cells to larger medullary cells, pseudoparenchymatous throughout with the outer cortex 2–3 cells thick (not in distinct rows), outermost cells 3–7 µm in diameter and L/D 1–1.5, with a secondary cortex developing below; secondary pit-connections and cell globules common (Fig. 11C), the latter especially in cap cells, pericarp cells and cells of nemathecial paraphyses; medullary cells (20–) 40–90 µm in diameter, walls 2–3 µm thick. Rhodoplasts discoid.

Reproduction: Carpogonial branches not observed. Carposporophyte (Fig. 11D) with a dense gonimoblast reticulum involving a small basal fusion cell, fusions between gonimoblast and gametophyte cells, and other fusion centres, with a dense tuft of erect gonimoblast filaments terminating in straight chains of numerous ovoid to subspherical carposporangia 8–15 µm in diameter, maturing apically. Cystocarps scattered on upper branches, radial, hemispherical to globular, 0.7–1 mm across; pericarp (Fig. 11D) massive, with inner tangentially elongate cells and outer anticlinal rows 5–8 µm in diameter, with an ostiole. Possible spermatangial sori scattered on upper branches, with anticlinal cell rows releasing terminal cells as spermatia(?).

Tetrasporangial nemathecia (Fig. 11E) surrounding branches below apices, distinct, 45–90 µm thick, paraphyses elongate-clavate, 3–5 cells long, 4–6 µm in diameter, with prominent globules; tetrasporangia basally pit-connected to upper cells of paraphyses, 20–25 µm long and 8–11 µm in diameter, cruciately divided.

Type from Queenscliff, Vic. (Mueller); lectotype (here designated) in Herb. Agardh, LD, 28642.

Selected specimens: Near Isles of St Francis, S. Aust., 37 m deep (Symonds, 23.x.1973; AD, A44256). Elliston, S. Aust., 10–12 m deep outside bar (Shepherd, 25.x.1971; AD, A42669). Wanna, S. Aust., drift (Womersley, 19.ii.1959; AD, A22363). Oedipus Point, West I., S. Aust., 10 m deep (Shepherd, Dec. 1966; AD, A31129). Whale Point, West I., S. Aust., 26 m deep (Shepherd, June 1966; AD, A30612). Vivonne Bay, Kangaroo I., S. Aust., drift (Womersley, 2.i.1949; AD, A10655). Robe, S. Aust., drift (Womersley, 15.iv.1959; AD, A23009 and 24.viii.1960; AD, A24401). 1.35 km off Middle Point, Cape Northumberland, S. Aust., 15 m deep (Johnson, 13.vii.1974; AD, A45455). Lady Julia Percy I., Vic., 8–11 m deep (Shepherd, 3.i.1968; AD, A32471). Walkerville, Vic., drift (Sinkora A2593, 29.iii.1979; AD, A61004). Erith I., Bass Strait, 5–7 m deep (Riddle, 20.ii.1990; AD, A60456).

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

Distribution: Isles of St Francis, S. Aust., to Walkerville, Vic., and Erith I., Bass Strait. New Zealand?

Taxonomic notes: Melanthalia concinna is essentially a deep water species on rough-water coasts.

There has been some confusion with Fucus concinnus R. Brown ex Turner [= Trematocarpus concinnus (R. Brown ex Turner)De Toni], based on Brown specimens from Kent I., Bass Strait, but all Brown specimens in BM appear to be Trematocarpus, and Melanthalia concinna J. Agardh was based on other southern Australian material.

It is doubtful if Chapman's (1979, p. 312, pl. 117) description of M. concinna from New Zealand does apply to this Australian species.


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

CHAPMAN, V.J. (1979). The marine algae of New Zealand. Part III: Rhodophyceae. Issue 4: Gigartinales, pp. 279–509. (Cramer: Germany.)

DE TONI, G.B. (1900b). Sylloge Algarum omnium hucusque Cognitarum. Vol. 4. Florideae. Sect. 2, pp. 387–776. (Padua.)

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

LUCAS, A.H.S. (1929b). A census of the marine algae of South Australia. Trans. R. Soc. S. Aust. 53, 45–53.

MAY, V. (1965). A census and key to the species of Rhodophyceae (red algae) recorded from Australia. Contr. N.S.W. natn. Herb. 3, 349–429.

REINBOLD, T. (1897). Die Algen der Lacepede und Guichen Bay und deren näherer Umgebung (Süd Australien), gesammelt von Dr. A. Engelhart-Kingston. Nuova Notarisia 8, 41–62.

SONDER, O.W. (1881). In Mueller, F., Fragmenta Phytographiae Australiae. Supplementum ad volumen undecinum: Algae Australianae hactenus cognitae, pp. 1–42, 105–107. (Melbourne.)

TISDALL, H.T. (1898). The algae of Victoria. Rep. 7th Meet. Aust. Ass. Adv. Sci., Sydney, 1898, pp. 493–516.

WOMERSLEY, H.B.S. (1950). The marine algae of Kangaroo Island. III. List of Species 1. Trans. R. Soc. S. Aust. 73, 137–197.

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

Author: H.B.S. Womersley

Publication: Womersley, H.B.S. (28 June, 1996)
The Marine Benthic Flora of Southern Australia
Rhodophyta. Part IIIB. Gracilarialse, Rhodymeniales, Corallinales and Bonnemaisoniales
Reproduced with permission from The Marine Benthic Flora of Southern Australia Part IIIB 1996, by H.B.S. Womersley. Australian Biological Resources Study, Canberra. Copyright Commonwealth of Australia.

Illustration in Womersley Part IIIA, 1996: FIG. 11.

Figure 11 image

Figure 11   enlarge

Fig. 11. Melanthalia concinna (A, AD, A32471; B, E, AD, A30612; C, D, AD, A24401). A. Habit. B. Transverse section of a branch. C. Longitudinal section through apical cap. D. Section of cystocarp with chains of carposporangia. E. Transverse section with tetrasporangia.

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