Electronic Flora of South Australia Species Fact Sheet

Sargassum podacanthum Sonder 1845: 51; 1848: 161.

Phylum Phaeophyta – Order Fucales – Family Sargassaceae

Selected citations: J. Agardh 1848: 323; 1889: 116. De Toni 1895: 97. Grunow 1915: 377. Kützing 1849: 609.

Thallus (Fig. 166B) medium to dark brown, 10–35 cm high, with a simple or branched stipe 1–4 cm long, terete, 1–2 mm in diameter, with stubby branch residues, bearing apically 1–3 primary branches. Holdfast discoid-conical, 2–10 mm across, with a single stipe. Primary branches 10–35 cm long, axes compressed below, terete to angular above, usually with short, scattered spines, radially branched. Laterals (lower) 1–4 cm long, 3–5 (–8) mm broad, simple, lanceolate, serrate, costate throughout, with more or less prominent cryptostomata, with acute or rounded apices; upper laterals 1–2 cm long, 1–2 (–3) mm broad, lanceolate, serrate and costate. Vesicles axillary, petiolate, subspherical, 2–4 mm in diameter, mutic.

Reproduction: Thalli monoecious. Receptacles (Fig. 168E) bisexual, simple or branched, in clusters 3–5 mm long, terete to slightly compressed, 700–1500 µm broad, slightly verrucose, with prominent, relatively massive, irregularly placed spines on most receptacles, apices rounded, with scattered ostioles. Conceptacles unisexual; oogonia sessile, subspherical to ovoid, 150–240 µm long and 100–180 µm in diameter, few per conceptacle; antheridia sessile or on branched paraphyses, clavate to ovoid, (14–) 16–26 µm long and (8–) 10–18 µm in diameter.

Type from W. Aust. (Preiss 2523); holotype in MEL, 1550994.

Selected specimens: Point Peron, W. Aust., upper sublittoral on reefs (Gordon, 15.xi.1968; ADU, A34356). Esperance, W. Aust., drift (Firman, Dec. 1951; ADU, A18914). 3 km S.E. of Marion Light, Gulf St Vincent, S. Aust., 24 m deep (Shepherd. 5.ii.1969; ADU, A33887). Troubridge I., S. Aust., 23 m deep (Shepherd, 4.ii.1969; ADU, A3381I). Marino, S. Aust., drift (Womersley, 11.xii.1960; ADU, A24690). Port Noarlunga, S. Aust., drift (Womersley, 30.xii.1975; ADU, A47027).

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

Distribution: From Point Peron, W.Aust., to Port Noarlunga, S. Aust., as isolated records.

Taxonomic notes: Sargassum podacanthum differs from S. spinuligerum in the presence of conspicuous, relatively massive, spines on the receptacles (Fig. 168E); the laterals also appear to be smaller and often more regularly spinous along the margins in the former. These differences need further study and it is possible the S. podacanthum is only a form of S. spinuligerum. The receptacles differ from those of S. distichum in lacking the lateral wings and in having spines produced in any direction rather than on two sides; however, ADU, A3381 I and A33887 do have slight upper wings to the receptacles, indicating possible intergrading with the latter species.

References:

AGARDH, J.G. (1848). Species, Genera et Ordines Algarum. Vol. 1. (Gleerup: Lund.)

AGARDH, J.G. (1889). Species Sargassorum Australiae. K. Svenska Vetenskapsakad. Handl. 23(3), 1–133, Plates 1–31.

DE TONI, G.B. (1895). Sylloge Algarum omnium hucusque Cognitarum. Vol. 3. Fucoideae. pp. 1–638. (Padua.)

GRUNOW, A. (1915). Additamenta ad cognitionem Sargassorum. Verh. Zool. -Bot. Wien 65, 329–448.

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

SONDER, O.W. (1845). Nova Algarum genera et species, quas in itinere ad oras occidentales Novae Hollandiae, collegit L. Preiss. Bot. Ztg 3, 49–57.

SONDER, O.W. (1848). Algae. In Lehmann, C., Plantae Preissianae. Vol. 2, pp. 161–195. (Hamburg.)

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

Author: H.B.S. Womersley & L.A. Scott

Publication: Womersley, H.B.S. (14 December, 1987)
The Marine Benthic Flora of Southern Australia
Part II
©Board of the Botanic Gardens and State Herbarium, Government of South Australia

Illustrations in Womersley Part II, 1997: FIGS 166B, 168E.

Figure 166   enlarge

Fig. 166. A. Sargassum spinuligerum (ADU, A45987). B. Sargassum podacanthum (ADU, A24690).

Figure 168   enlarge

Fig. 168. Receptacles of species of Sargassum. A. Sargassum lacerifolium (ADU, A55356), triquetrous receptacles. B,C. Sargassum linearifolium (B, ADU, A19095; C, ADU, A34191). B. Young receptacles. C. Mature receptacles. D. Sargassum spinuligerum (ADU, A39204). E. Sargassum podacanthum (ADU, A24690). F. Sargassum distichum (ADU, A24363).

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