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Laurencia aldingensis Saito & Womersley 1974: 821, figs 1B–D, 7.

Phylum Rhodophyta – Family Rhodomelaceae – Tribe Laurencieae

Thallus (Fig. 203A) medium red, often greenish below, tufted, 2–8 (–10) cm high and wide, cartilaginous, branching irregularly radial, dense, lower branches entangled, upper longer branches free, terete, slender, with fairly uniform diameter of 400–600 µm, ultimate branchlets 1–2 mm long, 1–3 mm apart. Attachment to host and itself by small pads and recurved branchlets; epiphytic on Sargassum and Cystoseira. Structure. Epidermal cells compact, outer walls (Fig. 205B) slightly convex near branch apices, isodiametric and 15–25 µm across near apices, 30–50 µm broad and L/D (1.5–) 2–3 (–4) below, with longitudinal secondary pit-connections; epidermal cells isodiametric in section, with corps en cerise, inner cells without lenticular thickenings. Cells uni- or multinucleate; rhodoplasts discoid, chained in larger cells.

Reproduction: Gametophytes dioecious. Procarps not observed. Carposporophytes with a slight basal fusion cell and short branched gonimoblast with clavate carposporangia 30–55 µm in diameter. Cystocarps (Fig. 203B, F) borne just below apices of branchlets, ovoid or slightly urceolate, sessile, 500–800 µm in diameter, broad based or slightly constricted; pericarp ostiolate with a slight neck, several cells thick. Spermatangia (Fig. 203C, G) borne on trichoblasts in terminal pyriform branchlets 400–800 (–1000) µm across.

Tetrasporangia (Fig. 203D, E) borne in slightly broader, terete, simple or branched ramuli 300–500 (–600) µm in diameter and 0.7–1.5 (–2) mm long, in parallel arrangement, cut off adaxially or abaxially from outer part of pericentral cells, 80–120 µm in diameter.

Type from Aldinga reef, S. Aust., on Sargassum decipiens in shallow pools near reef edge (Womersley, 25.xi.1973); holotype and isotypes in AD, A44448-"Marine Algae of southern Australia" No. 167.

Selected specimens: Venus Bay, S. Aust., upper sublittoral (Womersley, 13.ii.1954; AD, A19482). Port Broughton, S. Aust., in deeper hole (Womersley, 1.xii.1963; AD, A27045). Port Turton, S. Aust., 3–5 m deep on piles (Kraft; 17.ix.1973; AD, A44016). Aldinga, S. Aust., outer reef pools (Womersley, 16.i.1972; Ad, A41230).

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

Distribution: Venus Bay to Aldinga, S. Australia; probably more widespread.

Taxonomic notes: Saito & Womersley (1974, p. 823) compared L. aldingensis to L. intricata Lamouroux from the Antilles, suggesting that while probably distinct, further detailed comparisons are needed. Relationships with other slender species (e.g. L. filiformis f. filiformis) also need further study.


SAITO, Y. & WOMERSLEY, H.B.S. (1974). The southern Australian species of Laurencia (Ceramiales: Rhodophyta). Aust. J. Bot. 22, 815–874.

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

Publication: Womersley, H.B.S. (24 February, 2003)
The Marine Benthic Flora of Southern Australia
Rhodophyta. Part IIID. Ceramiales – Delesseriaceae, Sarcomeniaceae, Rhodomelaceae
Reproduced with permission from The Marine Benthic Flora of Southern Australia Part IIID 2003, by H.B.S. Womersley. Australian Biological Resources Study, Canberra. Copyright Commonwealth of Australia.

Illustrations in Womersley Part IIIA, 2003: FIGS 203, 205B.

Figure 203 image

Figure 203   enlarge

Fig. 203. Laurencia aldingensis (AD, A44448). A. Habit. B. Cystocarpic thallus. C. Spermatangial thallus. D, E. Tetrasporangial thalli. F. Cystocarp. G. Spermatangial receptacles. (A–E, as in Saito & Womersley 1974, courtesy of Aust. J. Bot.)

Figure 205 image

Figure 205   enlarge

Fig. 205. A. Laurencia majuscula (AD, A41231). Transverse section. B. Laurencia aldingensis (AD, A44448). Longitudinal section. C. Laurencia forsteri (AD, A41855). Transverse section with lenticular thickenings. D. Laurencia clavata (AD, A42231). Longitudinal section. E. Laurencia shepherdii (AD, A42795). Longitudinal section. F. Laurencia arbuscula (AD, A42244). Transverse section. (All as in Saito & Womersley 1974, courtesy of Aust. J. Bot.)

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