Electronic Flora of South Australia Species Fact Sheet

Asteronema ferruginea (Harvey) Delépine & Asensi 1975: 296, fig. 5.

Phylum Phaeophyta – Order Ectocarpales

Synonyms

Cladophora ferruginea Harvey 1859b: 340.

Sphacella ferruginea (Harvey) Womersley 1967: 194, fig. 1. Clayton 1974: 800, fig. 33.

Thallus (Fig. 2A) densely tufted or matted, epiphytic on Hormosira, Xiphophora, or rarely epilithic, usually 0.5–1.5 cm long. Filaments basally branched and attached by rhizoidal filaments (Fig. 3B), erect filaments (Fig. 3A) usually little-branched below and with more frequent branches above, of uniform thickness throughout, 15–22 µm in diameter, cells L/B 1.5–2.5 (–4), terminal phaeophycean hairs occasional (Fig. 3C). Growth from elongate apical cells (Fig. 3A,C) with rounded ends, with occasional intercalary divisions below. Cells with elongate phaeoplasts radiating from the central axile region (Fig. 3D), or appearing laminate or coalesced in older or preserved cells (Fig. 3C); pyrenoids doubtfully present, small physodes present.

Reproduction: Plurilocular gametangia (Fig. 3E,F) sessile or pedicellate, ovoid to conical, 50–85 µm long and 35–50 µm broad. Unilocular sporangia (Fig. 3A,D) pedicellate, subspherical to ovoid, 30–60 (–70) Aim long.

Type from Safety Cove, Port Arthur, Tas., on Hormosira; in TCD. Isotype in ADU, A 18166.

Selected specimens: West Beach, Robe, S. Aust., on Hormosira, lower eulittoral (Skinner, 14.xi.1978; ADU, A50221). Beachport, S. Aust., on Hormosira, lower eulittoral (Skinner, 14.xi.1978; ADU, A50222). Cape Bridgewater, Vic., on Hormosira in fairly high pool (Womersley, 29.xii.1981; ADU, A52853). Cape Marengo, Vic. on Xiphophora chondrophylla in lower eulittoral pools (Womersley, 13.x.1985; ADU, A56963). Curtis I., Bass Strait (King, Feb. 1971; MELU 21231, ADU, A43051). Bicheno, Tas., on Hormosira, upper sublittoral pools ( Wollaston & Mitchell, 2.iii.1964; ADU, A28008). Dover, Tas., on Hormosira, upper sublittoral (Gordon, 14.i.1966; ADU, A30002). Safety Cove, Port Arthur, Tas., on Hormosira, mid eulittoral pools (Skinner, 21.ii.1978; ADU, A49198-"Marine Algae of southern Australia" No. 191).


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

Distribution: From Robe, S. Aust., to Point Roadknight, Vic. and Curtis I., Bass Strait, and around Tasmania.

Taxonomic notes: Asteronema ferruginea appears to be a summer annual, known mainly from November to March (from September-Clayton 1974, p. 800) and normally epiphytic on Hormosira,

occasionally on Xiphophora, under strong water movement; Clayton (1974, p. 800) records it also on Corallina, the barnacle Balanus and on rocks.

A. ferruginea is closely related to A. australe Delépine & Asensi (1975) and it is doubtful if the latter is distinct. Delépine & Asensi reported a pyrenoid present in the cells and illustrated physodes, but their figures are not convincing, and they did not report hairs present in the type. A. ferruginea does not apparently have pyrenoids or physodes though this needs checking in living material, and occasional phaeophycean hairs are present on some plants.

References:

CLAYTON, M.N. (1974). Studies on the development, life history and taxonomy of the Ectocarpales (Phaeophyta) in southern Australia. Aust. J. Bot. 22, 743–813.

DELÉPINE, R. & ASENSI, A. (1975). Asteronema nov. gen. nouveau genre de Pheophycee australe. Bull. Soc. bot. Fr. 122, 295–304.

HARVEY, W.H. (1859b). Algae. In Hooker, J.D., The Botany of the Antarctic Voyage. Part III. Flora Tasmaniae. Vol. 2, pp. 282–343, Plates 185–196.

WOMERSLEY, H.B.S. (1967). A critical survey of the marine algae of southern Australia. II. Phaeophyta. Aust. J. Bot. 15, 189–270.

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 2A, 3.

Figure 2 image

Figure 2   enlarge

Fig. 2. A. Asteronema ferruginea on Hormosira (ADU, A52853). B. Bachelotia antillarum (ADU, A49210). C. Kuckuckia spinosa on Amphibolis (ADU, A39457). D. Ectocarpus siliculosus (ADU, A54422). E. Ectocarpus fasciculatus on Ecklonia (ADU, A32006).

Figure 3 image

Figure 3   enlarge

Fig. 3. Asteronema ferruginea (A, B, D, ADU, A28008; C, ADU, A49198; E, ADU, A30002; F, MELU, 21231; ADU, A43051). A. Branching filaments showing apical cells and unilocular sporangia. B. Base of thallus with branched, multicellular rhizoids. C. Branches, the right with an apical cell and the left with a phaeophycean hair. D. Cells showing elongate radiating phaeoplasts, and unilocular sporangia. E. Young(?) plurilocular sporangia. F. Plurilocular sporangium.


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