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Electronic Flora of South Australia Species Fact Sheet

Gymnothamnion elegans (Schousboe ex C. Agardh)J. Agardh 1892: 28, p1. 1 figs 11–14.

Phylum Rhodophyta – Order Ceramiales – Family Ceramiaceae – Tribe Gymnothamnieae

Selected citations: Athanasiadis 1987: 68. Balakrishnan 1958: 138, figs 1–14. Feldmann & Feldmann 1966: 10, figs 2–6. Itono 1977: 40, figs, 20, 42A, B, 72J–Z. Kajimura 1989: 122, figs 1–21. Millar & Kraft 1993:41. Moe & Silva 1979: 397. Silva et al. 1996: 413. Stegenga 1986: 84, pls 28, 29. Stegenga et al. 1997: 434, pl. 168 figs 1–3.

Synonym

Callithamnion elegans Schousboe ex C. Agardh 1828: 162.

Thallus (Fig. 57B) 2–5 mm high, with prostrate filaments bearing ecorticate plumose erect axes with opposite, distichous, simple or slightly branched branchlets (Fig. 57E) from each axial cell; erect axes mostly unbranched, occasionally with lateral branches developed from one of the paired branchlets. Attachment by multicellular rhizoids with branched ends, developed from cells (several cells apart) of the prostrate filaments, usually with an opposite erect branch. Structure. Apical cells (Fig. 57C) of axes 7–15 µm in diameter and L/D 1–1.5 (–2.5), increasing to axial cells 10–15 nm in diameter and L/D 1.5–3 (Fig. 57D, E). Branchlets simple or with adaxial (and abaxial near the apices) branches, 60–180 (–240) µm and 3–9 (–12) cells long, cells 6–9 µm in diameter and L/D 1.5–2.5 (–3). Cells uninucleate; rhodoplasts elongate.

Reproduction: Gametophytes probably dioecious. Procarps (Fig. 56I, J) developed mainly on shorter (3–6 short cells), opposite, upwardly curved, branchlets along the erect axes, separated by 2 pairs of sterile branchlets, sometimes near the end of full length branchlets. Fertile branchlets with the subterminal cell bearing a supporting cell with a 4-celled carpogonial branch and a sterile cell (occasionally with 2 or 3 successive procarps) with 1–2 hypogenous cells usually cutting off a lateral cell. Carposporophytes (unknown in this material) reported as pyramidal or elongate lobes. Spermatangia (unknown in Australian material) terminal or lateral on short branchlets.

Tetrasporangia (Fig. 56K) terminal on branchlets, ovoid, 20–25 µm in diameter, tetrahedrally divided.

Type from Tangier, Morocco; in Herb. Agardh, LD.


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

Distribution: Widespread (but inconspicuous) in warmer seas.

In southern Australia, known only from Point Lonsdale, Vic., on sponge under overhang, 0.3 m deep (Kraft 7810 & Millar, 25.iii.1988; MELU and AD, A67814) and Bicheno, Tas., on tunicate, 17–19 m deep (Kraft 9362, 18.xii.1992; MELU and AD, A67815). Also N.S.W. (Millar & Kraft 1993, p. 41).

Taxonomic notes: The southern Australian specimens agree well in habit, structure and dimensions with descriptions of G. elegans by Feldmann & Feldmann (1966), Balakrishnan (1958) and Stegenga (1986, p. 84, pls 28, 29), but with minor differences. No secretary (gland) cells such as illustrated by (only?) Feldmann & Feldmann (fig. 1B) have been observed, and there appears to be a sterile cell on the supporting cell rather than a second periaxial cell, as described by Balakrishnan (1958, p. 139). However, the Bicheno material had not been fertilized and further observations are needed on the procarp structure.

References:

AGARDH, C.A. (1828). Species Algarum. Vol. 2, pp. 1–189. (Mauritius: Greifswald.)

AGARDH, J.G. (1892). Analecta Algologica. Acta Univ. lund. 28, 1–182, Plates 1–3.

ATHANASIADIS, A. (1987). A survey of the seaweeds of the Aegean Sea with taxonomic studies on the species of the tribe Antithamnieae (Rhodophyta). (University of Gothenburg, Department of Marine Botany.)

BALAKRISHNAN, M.S. (1958). Notes on Indian red algae. J. Indian Bot. Soc. 37, 138–146.

FELDMANN, J. & FELDMANN, G. (1966). Sur le Gymnothamnion elegans (Shousboe)J. Ag. et la situation des organes femelles chez les Céramiacées. Revue gén. Bot. 73, 5–17, Plate 1.

ITONO, H. (1977). Studies on the Ceramiaceous algae (Rhodophyta) from southern parts of Japan. Bibliotheca Phycologia 35, 1–499.

KAJIMURA, M. (1989). Gymnothamnieae trib. nov. (Ceramiaceae, Rhodophyta). Bot. Mar 32, 121–130.

MILLAR, A.J.K. & KRAFT, G.T. (1993). Catalogue of marine and freshwater Red Algae (Rhodophyta) of New South Wales, including Lord Howe Island, South-western Pacific. Aust. Syst. Bot. 6, 1–90.

MOE, R.L. & SILVA, P.C. (1979). Morphological and taxonomic studies on Antarctic Ceramiaceae (Rhodophyceae). I. Antarcticothamnion polysporum gen. et sp. nov. Br. phycol. J. 14, 385–405.

SILVA, P.C., BASSON, P.W. & MOE, R.L. (1996). Catalogue of the Benthic Marine Algae of the Indian Ocean. (University of California Press: Berkeley, Los Angeles & London.)

STEGENGA, H. (1986). The Ceramiaceae (excl. Ceramium) (Rhodophyta) of the South West Cape Province, South Africa. Bibl. Phycol. 74, 1–149.

STEGENGA, H., BOLTON, J.J. & ANDERSON, R.J. (1997). Seaweeds of the South African West Coast. Contributions from the Bolus Herbarium, No. 18.

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

Author: H.B.S. Womersley

Publication: Womersley, H.B.S. (24 December, 1998)
The Marine Benthic Flora of Southern Australia
Rhodophyta. Part IIIC. Ceramiales – Ceramiaceae, Dasyaceae
©State Herbarium of South Australia, Government of South Australia


Illustration in Womersley Part IIIA, 1998: FIG. 57 B–E.

Figure 57 image

Figure 57   enlarge

Fig. 57. A. Gymnothamnion nigrescens (slide of type fragment, AD, A 18386). Branching of axes, with opposite branchlets bearing adaxial branches. B–E. Gymnothamnion elegans (B–E, MELU, K9362; AD, A67815). B. Branched axes with opposite branchlets. C. Apex of axis with developing opposite branchlets. D. Mature axis and branchlets with procarps. E. Axis with short opposite branchlets bearing procarps.


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