Electronic Flora of South Australia Species Fact Sheet

Stictyosiphon soriferus (Reinke) Rosenvinge 1935: 9, figs 9–19.

Phylum Phaeophyta – Order Dictyosiphonales – Family Striariaceae

Selected citations: Lewis 1983: 261. Naylor 1958: 16, figs 1C,D, 2C,D,G, 3C. Skinner & Womersley 1983: 63, figs 1B, 2G–L. South & Hooper 1976: 24, figs 3–8.

Thallus (Fig. 109C) light to medium brown, 10–15 (–30) cm high, slender, terete, much branched irregularly alternately (frequently opposite when young), tapering gradually from base to apices; attachment by a small, discoid, rhizoidal holdfast, epilithic. Structure below the apical trichothallic filament uniseriate (Fig. 113E,F) for 10–50 cells, (10–) 15–20 µm in diameter with cells L/B 0.3–0.7, becoming polystichous (Fig. 113G,H) below and 30–40 µm in diameter in upper branches, 200–400 µm in diameter in lower branches, branches solid apart from oldest parts, with a monostromatic, small-celled, cortex of phaeoplastic cells, more or less isodiametric and angular, 15–30 (–35) µm across in surface view and L/B 1–2, and a large-celled medulla (Fig. 113J) of 3–5 rounded, isodiametric cells with smaller cells below the cortex in older branches; cells in tiers in young branches, less so in older parts with the cortical cells subdividing and 4–8 within the old cell wall; phaeoplasts numerous per cell, each with a pyrenoid, and with prominent physodes. Phaeophycean hairs numerous, usually solitary, scattered, 5–8 (–10) µm in diameter.

Microthallus filamentous, pulvinate (unknown for Australian plants); macrothallus reproduced directly (South & Hooper 1976).

Reproduction: Plurilocular sporangia (Fig. 1131,J) in scattered patches, formed by subdivision of one or a small group of cortical cells and slightly raised above the cortex, 20–40 µm across in surface view with 4–6 locules in face view, each 2–4 locules high, each locule 2–3 µm across.

Type from the West Baltic Sea; lectotype in KIEL (and BM) (Naylor 1958, p. 17).

Selected specimens: Princess Royal Harbour, Albany, W. Aust., upper sublittoral ( Womersley, 21.viii.1979; ADU, A51388). Billy Lights Point, Port Lincoln, S. Aust., 12 m deep on Pinna (Shepherd, 23.viii.1975; ADU, A46532). Kirk Point, Port Phillip, Vic., uppermost sublittoral (Womersley, 30.viii. I 981; ADU, A53230).

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

Distribution: North Atlantic; Mediterranean.

In southern Australia, from Albany, W. Aust. to Port Phillip, Vic., in harbours.

Taxonomic notes: S. soriferus is probably also an introduction from the North Atlantic. The above specimens agree with S. soriferus in having alternate branching, being solid throughout, in cortical cell size, and in having rounded phaeoplasts (Naylor 1958, p. 17).


LEWIS, J.A. (1983). Floristic composition and periodicity of subtidal algae on an artificial structure in Port Phillip Bay (Victoria, Australia). Aquatic Bot. 15, 257–274.

NAYLOR, M. (1958). Observations on the taxonomy of the genus Stictyosiphon Kiitz. Rev. Algol., N.S., 4, 7–24.

ROSENVINGE, L.K. (1935). On some Danish Phaeophyceae. Mem. Acad. R. Sci. Lett. Dan., Copenhague, Sect. Sci., Ser. 9, 6(3), 1–40.

SKINNER, S. & WOMERSLEY, H.B.S. (1983). New records (possibly introductions) of Striaria, Stictyosiphon and Arthrocladia (Phaeophyta) for southern Australia. Trans. R. Soc. S. Aust. 107, 59–68.

SOUTH, G.R. & HOOPER, R. (1976). Stictyosiphon soriferus (Phaeophyta, Dictyosiphonales) from eastern North America. J. Phycol. 12, 24–29.

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

Author: H.B.S. Womersley

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 109C, 113 E–J.

Figure 109 image

Figure 109   enlarge

Fig. 109. A. Hydroclathrus clathratus (ADU, A56955). B. Striaria attenuata (ADU, A49759). C. Stictyosiphon soriferus (ADU, A53230).

Figure 113 image

Figure 113   enlarge

Fig. 113. A–D. Striaria attenuata (ADU, A49759). A. Diagram of thallus with sori and phaeophycean hairs. B. Apex of a branch with apical filament and showing segmentation. C. Surface view of part of a sorus of unilocular sporangia and paraphyses (shown with physodes and phaeoplasts). D. Transverse section of thallus showing cortical cells (with phaeoplasts and physodes) and a sorus of unilocular sporangia with a phaeophycean hair and two paraphyses (lightly stippled). E–J. Stictyosiphon soriferus (ADU, A53230). E. Apex of a branch with a terminal phaeophycean hair and part of long, uniseriate, filament. F. Lower part of branch with some longitudinal cell divisions and two lateral branches. G. Cell arrangement of older branch. H. Cells in subdivided tiers in older branch. I. Mature branch with surface view of plurilocular sporangia. J. Transverse section of branch with plurilocular sporangia in cortex and four large medullary cells.

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