Electronic Flora of South Australia Species Fact Sheet

Stenocladia furcata (Harvey) J. Agardh 1872: 45; 1876: 439.

Phylum Rhodophyta – Class Florideophyceae – Order Gigartinales – Family Nizymeniaceae

Selected citations: De Toni 1900: 404. Kylin 1932: 51. Searles 1968: 39, fig. 17, pl. 8a. Womersley 1971b: 201, fig. 3.

Synonym

Heringia furcata Harvey 1862: pl. 215; 1863, synop.: xxxiii.

Thallus (Fig. 139A) erect, dark red-brown, 10–25 cm high, subdichotomously and radially branched at intervals of 0.5–2 cm, branches terete, 1–1.7 mm in diameter below, decreasing gradually to 300–500 µm in diameter near the rounded apices. Holdfast discoid, 2–5 mm across, with one to a few stipes; epilithic. Structure uniaxial, with 3 or 4 (Fig. 139B, C) periaxial cells, developing a filamentous medulla of thick-walled rhizoids 3–6 µm in diameter around the prominent axial filament 70–120 µm in diameter, with a broad pseudoparenchymatous cortex of angular cells, inner cells 15–25 (–30) µm across, outer cells 4–6 µm in diameter and L/D 1–1.5. Rhodoplasts discoid, becoming ribbon shaped in inner cortical cells.

Reproduction: Sexual thalli dioecious. Cystocarps subspherical, basally constricted, 400–800 µm in diameter; carposporophyte with a central to basal fusion cell and dense, radiating gonimoblast filaments bearing terminal chains of 3–4 ovoid carposporangia 5–9 µm in diameter; pericarp thick, dense, ostiolate. Spermatangia formed on laterals (usually in threes) of uniseriate filaments (Fig. 139D) 15–25 µm in diameter, arising in tufts (Fig. 139C) on the thallus surface.

Tetrasporangia (with only a median division) only seen on spermatangial filaments (Fig. 139D), subspherical, 12–15 µm in diameter.

Lectotype from Port Phillip Heads, Vic.; in Herb. Harvey, TCD (Alg. Aust. Exsicc. 311).

Selected specimens: Encounter Bay, S. Aust., drift (Harris, Dec. 1943; AD, A1893). Robe, S. Aust., drift (Wollaston, 13.iii.1955; AD, A19917; Womersley, 18.v.1964; AD, A27852 and 9.ix.1968; AD, A32725). 11 km off Cape Northumberland, S. Aust., 48 m deep (Shepherd, 6.v.1975; AD, A46303). Port MacDonnell, S. Aust., drift (Womersley, 15.iv.1959; AD, A22986). Point Roadknight, Vic., drift (Womersley, 6.vi.1953; AD, A18778). Port Phillip Heads, Vic. (AD, A8293).


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

Distribution: Encounter Bay, S. Aust., to Port Phillip Heads, Vic.

Taxonomic notes: S. furcata is similar to S. australis in its reproduction but clearly differs in branch morphology.

References:

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.)

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

HARVEY, W.H. (1862). Phycologia Australica. Vol. 4, Plates 181–240. (Reeve: London.)

HARVEY, W.H. (1863). Phycologia Australica. Vol. 5, Plates 241–300, synop., pp. i-lxxiii. (Reeve: London.)

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

SEARLES, R.B. (1968). Morphological studies of red algae of the order Gigartinales. Univ. Calif Pubis Bot. 43, vi + 1–86, Plates 1–12.

WOMERSLEY, H.B.S. (1971b). The relationships of Nizymenia and Stenocladia (Gigartinales, Rhodophyta). Phycologia 10, 199–203.

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.


Illustration in Womersley Part IIIA, 1994: FIG. 139.

Figure 139 image

Figure 139   enlarge

Fig. 139. Stenocladia furcata (A, AD, A19917; B, AD, A27852; C, D, AD, A32725). A. Habit. B. Transverse section of branch showing axial filament with three periaxial cells. C. Transverse section of branch with tuft of male filaments; axial filament with four periaxial cells. D. Detail of filaments with laterals bearing spermatangia and a few tetrasporangia (arrows).


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