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Electronic Flora of South Australia Species Fact Sheet

Perithamnion muelleri (Harvey) Womersley, comb. nov.

Phylum Rhodophyta – Order Ceramiales – Family Ceramiaceae – Tribe Heterothamnieae


Crouania muelleri Harvey 1863, synop.: xlix. J. Agardh 1876: 85. De Toni 1903: 1419. Lucas 1909: 51. Sonder 1881: 12.

Thallus (Fig. 95A) medium red-brown, 2–10 (–15) cm high, ecorticate, much branched irregularly radially with long laterals from lower axes, often with laterals 4–5 cells apart on upper branches, axial cells with 5 whorl-branchlets (Fig. 95B) in distinct whorls. Attachment by branches with recurved ends or by rhizoids; epiphytic or epilithic. Structure. Apical cells 6–8 µm in diameter and L/D 1–2, partly surrounded by young whorl-branchlets, enlarging to axial cells in mid thallus 120–240 µm in diameter and L/D 1–1.2, and in lower axes cells 350–500 µm in diameter and L/D 1–2.5; axial cells conspicuous throughout thallus, with gaps between whorl-branchlets 40–90 µm broad in lesser branches, increasing to 400–500 µm broad in lower axes (2–3 times the length of the whorls of whorl-branchlets). Whorl-branchlets normally 5 per axial cell, evenly spaced, becoming 200–300 µm long with 5–7 successive di- to quadrichotomous branches from the basal cells, basal cells 20–30 µm in diameter and L/D 1–1.5, decreasing to terminal cells 6–8 µm in diameter and L/D 1.5–2, often with long multicellular hairs; gland cells usually prolific, on mid to outer cells of the whorl-branchlets, arising on terminal cells and touching only the bearing cell, sessile, subspherical to ovoid, 10–15 µm in diameter. Lateral branches arising from basal cells of whorl-branchlets. Cells multinucleate; rhodoplasts discoid, forming a reticulum or ribbon like in larger cells.

Reproduction: Gametophytes dioecious. Carpogonial branches on the basal (= supporting) cell of whorl-branchlets, single per whorl and on 1–3 successive whorls. Post fertilization the supporting cell cuts off a larger, lateral, auxiliary cell which develops a terminal and lateral gonimolobes (Fig. 95B) 160–220 µm across of ovoid carposporangia 20–30 µm in diameter. The axial cell, residual supporting cell, auxiliary cell and lower gonimoblast cells fuse somewhat, with broader pit-connections. No involucral filaments develop and the carposporophytes remain more or less terminal on branches. Spermatangia (Fig. 95C, D) cut off from initials on terminal cells of whorl-branchlets.

Tetrasporangia (Fig. 95E) borne on mid cells of whorl-branchlets, situated above the whorl-branchlets, sessile, subspherical, 35–55 µm in diameter, decussately divided.

Type from Phillip I., Western Port, Vic. (Mueller); lectotype (female) in Herb. Harvey, TCD; isolectotype (female) in MEL, 8435. The specimen designated as "TYPE" by HBSW in 1952 appears sterile, and it would be better to select an alternative female specimen as lectotype.

Selected specimens: Eyre, W. Aust., drift (Woelkerling, 22.xi.1968; AD, A34242). Point Sinclair, S. Aust., drift (Womersley, 25.i.1951; AD, A13884). Investigator Strait, S. Aust., 31 m deep (Watson, 25.i.1971; AD, A38186). Tiparra Reef, Spencer Gulf, S. Aust., on Amphibolis griffithii, 11 m deep (Shepherd, 31.x.1970; AD, A37691 - "Marine Algae of southern Australia" No. 396a). Inside Tapley Shoal, Gulf St Vincent, S. Aust., 13 m deep (Shepherd, 2.0.1969; AD, A33550 - "Marine Algae of southern Australia" No. 396). Middleton, S. Aust., drift (Womersley, 14.xi.1965; AD, A29708). Vivonne Bay, Kangaroo I., S. Aust., drift (Womersley, 14.i.1948; AD, A6849). Pennington Bay, Kangaroo I., S. Aust., eulittoral pool (Womersley, 19.i.1948; AD, A6502). N end Waratah Bay, Vic., on Polysiphonia decipiens, drift (Sinkora A2406,28.ii.1978; AD, A53594).

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

Distribution: Eyre, W. Aust., to Waratah Bay, Victoria.

Taxonomic notes: P. muelleri occurs mainly in deep water in moderately sheltered situations. It is a larger species than P. ceramioides and agrees in structure and reproduction, notably in having spermatangia cut off terminally from end cells of the whorl-branchlets. However, lateral branches appear to arise mainly on the basal cells of whorl-branchlets, so that the lateral is one of 5 in each whorl, pit-connected at the same level as the other 4.


AGARDH, J.G. (1876). Species Genera et Ordines Algarum. Vol. 3, Part 1- Epicrisis systematic Floridearum, pp. i-vii, 1–724. (Weigel: Leipzig.)

DE TONI, G.B. (1903). Sylloge Algarum omnium hucusque Cognitarum. Vol. 4. Florideae. Sect. 3, pp. 775–1521 + 1523–1525. (Padua.)

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

LUCAS, A.H.S. (1909). Revised list of the Fucoideae and Florideae of Australia. Proc. Linn. Soc. N.S.W. 34, 9–60.

SONDER, O.W. (1881). In Mueller, F., Fragmenta Phytographiae Australiae. Supplementum ad volumen undecinum: Algae Australianae hactenus cognitae, pp. 1–42, 105–107. (Melbourne.)

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

Author: H.B.S. Womersley & E.M. Wollaston

Publication: Womersley, H.B.S. (24 December, 1998)
The Marine Benthic Flora of Southern Australia
Rhodophyta. Part IIIC. Ceramiales – Ceramiaceae, Dasyaceae
©State Herbarium of South Australia, Government of South Australia

Illustration in Womersley Part IIIA, 1998: FIG. 95.

Figure 95 image

Figure 95   enlarge

Fig. 95. Perithamnion muelleri (A, AD, A37691; B, D, AD, A33607; C, AD, A41224; E, AD, A37691). A. Habit. B. Branches with whorl-branchlets and a carposporophyte. C. Branches with whorl-branchlets bearing terminal spermatangia. D. Whorl-branchlets with terminal spermatangia. E. Branch with whorl-branchlets bearing tetrasporangia.

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