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Lomentaria monochlamydea (J. Agardh) Kylin 1931: 27, pl. 13 fig. 30.

Phylum Rhodophyta – Class Florideophyceae – Order Rhodymeniales – Family Lomentariaceae

Selected citations: May 1965: 361.


Chylocladia monochlamydea J. Agardh 1890: 22; 1896: 87. De Toni 1900b: 576. Tisdall 1898: 506. Wilson 1892: 180.

Thallus (Fig. 59A) dark red-brown, forming entangled clumps 2–5 cm high and across, with basal stolons producing erect, mostly simple, compressed blades 0.5–2 cm high and 0.5–2 mm broad, basally constricted and tapering to a rounded apex. Stolons branched, often curved, with erect blades 1–3 (–5) mm apart, terete and 300–800 µm in diameter, attached by small haptera to the substrate or other branches; epilithic or on solid substrates. Structure multiaxial, with apical cells producing an interconnected network of medullary filaments 4–6 µm in diameter and bearing ovoid secretory cells 5–8 µm in diameter. Cortex (Fig. 59B) 3–4 cells thick, the inner cortex of 2–3 cells with an outer layer of ovoid or isodiametric cells 10–22 µm across, a mid layer of slightly larger cells and an inner layer of elongate cells connected to the medullary filaments and also bearing occasional secretory cells, and a sparse outer cortex of small cells, scarcely forming rosettes. Older parts and stolons hollow but cortex 4–6 cells thick. Branch constrictions (Fig. 59C) solid, pseudoparenchymatous. Rhodoplasts discoid, often in chains.

Reproduction: Gametangial thalli unknown.

Tetrasporangia in irregular, depressed, sori (Fig. 59D) 200–500 µm across, cut off inwardly from small cells lining the depression, subspherical to pyriform, 30–50 µm in diameter, tetrahedrally divided.

Type from Port Phillip Heads, Vic. (Wilson 19, 21.i.1886); holotype in Herb. Agardh, LD, 25818.

Selected specimens: Port Stanvac, S. Aust., 3–12 m deep on jetty piles (Clarke & Engler, 14.iv.1979; AD, A50342). Robe, S. Aust., 3 m deep on jetty piles (Kildea & Collings, 26.ix.1992; AD, A62822). Apollo Bay, Vic., 0–1 m deep on pipeline in harbour (Kraft 3719 & Owen, 2.ix.1971; MELU and AD, A39524). Gloucester Reserve, Williamstown, Vic., 2–4 m deep (Kraft 9466 & Williams, 27.x.1992; MELU, 42062; AD, A63399).

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

Distribution: Port Stanvac, S. Aust., to Port Phillip Heads, Vic., and Coffs Harbour, N.S.W. (Millar 1990, p. 375).

Taxonomic notes: This comparatively rare species was recorded from N.S.W. by Millar (1990, p. 375, fig. 31A–D) and Millar & Kraft (1993, p. 30). It is characterised by its stoloniferous base and small size with mainly irregular branching. Some more erect branches are subpinnate and resemble small branches of L. pyramidalis, but the latter has a single discoid holdfast, is a much larger species, and is usually epiphytic on Posidonia or Amphibolis.


AGARDH, J.G. (1890). Till algernes systematik. Acta Univ. lund. 26(3), 1–125, Plates 1–3.

AGARDH, J.G. (1896). Analecta Algologica. Cont. III. Acta Univ. lund. 32, 1–140, Plate 1.

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

KYLIN, H. (1931). Die Florideenordnung Rhodyméniales. Lunds Univ. Årsskr. N.F. Avd. 2, 27 (11), 1–48, Plates 1–20.

MAY, V. (1965). A census and key to the species of Rhodophyceae (red algae) recorded from Australia. Contr. N.S.W. natn. Herb. 3, 349–429.

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.

MILLAR, A.J.K. (1990). Marine Red Algae of the Coffs Harbour Region, northern New South Wales. Aust. Syst. Bot. 3, 293–593.

TISDALL, H.T. (1898). The algae of Victoria. Rep. 7th Meet. Aust. Ass. Adv. Sci., Sydney, 1898, pp. 493–516.

WILSON, J.B. (1892). Catalogue of algae collected at or near Port Phillip Heads and Western Port. Proc. R. Soc. Vict. 4, 157–190.

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

Author: H.B.S. Womersley

Publication: Womersley, H.B.S. (28 June, 1996)
The Marine Benthic Flora of Southern Australia
Rhodophyta. Part IIIB. Gracilarialse, Rhodymeniales, Corallinales and Bonnemaisoniales
Reproduced with permission from The Marine Benthic Flora of Southern Australia Part IIIB 1996, by H.B.S. Womersley. Australian Biological Resources Study, Canberra. Copyright Commonwealth of Australia.

Illustration in Womersley Part IIIA, 1996: FIG. 59.

Figure 59 image

Figure 59   enlarge

Fig. 59. Lomentaria monochlamydea (AD, A39524). A. Habit. B. Transverse section of thallus. C. Longitudinal section through a constriction. D. Surface view of tetrasporangial thallus.

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