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Electronic Flora of South Australia Species Fact Sheet

Feldmannia irregularis (Kützing) Hamel 1939b: xvii, fig. 61F.

Phylum Phaeophyta – Order Ectocarpales

Selected citations: Cardinal 1964: 54, fig. 29. Knoepffler-Péguy 1970: 173. Womersley 1967: 192.


Ectocarpus irregularis Kützing 1845:234. Hamel 1931: 45, fig. 13. Lindauer et al. 1961: 148, fig. 8. Rosenvinge & Lund 1941: 50, figs 23, 24. Sauvageau 1933: 101, figs 24–27.

Giffordia irregularis (Kützing) Joly. Clayton 1974: 777, figs 19,20.

Thallus (Fig. 6D) medium to dark brown, tufted, with numerous axes arising from a clumped base, mostly 0.2–1.5 (–3) cm long, much branched in the lower half with long unbranched filaments surmounting the meristematic regions (Fig. 8A), usually epiphytic. Filaments (Fig. 8B) 18–30 (–40) µm in diameter below with cells L/B (1.5–) 2–4, of fairly uniform diameter throughout and 20–35 µm in diameter above the upper meristem with cells becoming L/B 3–6 and with few phaeoplasts. Growth from meristems (Fig. 8B) at base of laterals and usually at intervals along main filaments, with occasional other diffuse divisions (especially where sporangia occur). Cells (Fig. 8C) with numerous discoid phaeoplasts, each with a pyrenoid, and aggregated physodes.

Reproduction: Plurilocular sporangia (Fig. 8C) usually sessile (rarely pedicellate), situated below upper meristems, single or in series of 2–3, often adaxial, of greatest diameter near their base and tapering markedly above, 60–100 µm long and 22–30 (–45) µm in diameter. Unilocular sporangia (Clayton 1974, fig. 19F) ovoid, sessile.

Type from the Adriatic Sea; in.L (?)-apparently not located (Clayton 1974, p. 779).

Selected specimens: Point Clune, Rottnest I., W. Aust., on Laurencia elata, 13–14 m deep (Walker, 6.xii.1984; ADU, A56634). Venus Bay, S. Aust., sublittoral fringe (Womersley, 12.ii.1954; ADU, A19537). Port Hughes, S. of Wallaroo, S. Aust., 1–3 m deep (Gordon-Mills, 22.xii.1983; ADU, A55417-"Marine Algae of southern Australia" No. 247). Aldinga, S. Aust., lower eulittoral pool, on Posidonia australis (Skinner, 25.vii.1978; ADU, A49432). Sandy R. mouth, Kangaroo I., S. Aust., low eulittoral pools (Womersley, 5.ii.1957; ADU, A20751). American R. inlet, Kangaroo I., S. Aust., on Scytosiphon on buoy (Womersley, 30.x.1966; ADU, A30871). Lorne, Vic. on Cystophora subfarcinata in low eulittoral pools (Womersley, 23.i.1967; ADU, A31540). Point Roadknight, Vic., on Notheia, low eulittoral pool ( Womersley, 11.iv.1959; ADU, A22596).

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

Distribution: Widespread in temperate waters.

In southern Australia, from Rottnest I., W. Aust. to Heron I., Qld. (Clayton 1974, p. 777); probably more widespread.

Taxonomic notes: F. irregularis was referred to Giffordia by Clayton (1974, p. 777), but most plants are typical of Feldmannia in having long unbranched filaments above the upper meristematic zones, and restriction of most sporangia to below these zones; it is, however, more branched in the lower parts than most species of Feldmannia, with distinct meristematic zones at the base of lateral branchlets, and the sporangia are sessile, as in species of Giffordia. Plants which resemble Giffordia have usually lost part of the long unbranched terminal filaments, and seem to be more common in warmer waters; it is, however, a bridging species between Feldmannia and Giffordia.


CARDINAL, A. (1964). Étude sur les Ectocarpacees de la Manche. Nova Hedwigia 15, 1–86, Figs. 1–41.

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.

HAMEL, G. (1931). Phéophycées de France. Fasc. I, pp. 1–80. (Paris.)

HAMEL, G. (1939b). Phéophycées de France. Fasc. V, pp. 337–432, i-xlvii. (Paris.)

KÜTZING, F.T. (1845). Phycologia Germanica. (Köhne: Nordhausen.)

KNOEPFFLER-PÉGUY, M. (1970). Quelques Feldmannia Hamel, 1939 (Phaeophyceae-Ectocarpales) des côtes d'Europe. Vie et Milieu Sér. A. 21, 137–188.

LINDAUER, V.W., CHAPMAN, V.J. & AIKEN, M. (1961). The marine algae of New Zealand. II. Phaeophyceae. Nova Hedwigia 3, 129–350, Plates 57–97.

ROSENVINGE, L.K. & LUND, S. (1941). The marine algae of Denmark. Vol. II. Phaeophyceae. I. Ectocarpaceae and Acinetosporaceae. K. Dan. Vidensk. Selsk. Biol. Skr. 1(4), 1–79.

SAUVAGEAU, C. (1933). Sur quelques Algues phéosporées de Guethary (Basses-Pyrenees). Bull. Stn biol. Arcachon 30, 1–128.

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 6D, 8 A–C.

Figure 6 image

Figure 6   enlarge

Fig. 6. A. Zosterocarpus australica (ADU, A38165, holotype). B. Sorocarpus micromorus (MELU 20519; ADU, A39499). C. Pilayella littoralis (ADU, A42709). D. Feldmannia irregularis (A22596). E. Feldmannia paradoxa on Scytosiphon (A31828). F. Feldmannia globifera (A19777).

Figure 8 image

Figure 8   enlarge

Fig. 8. A–C. Feldmannia irregularis (ADU, A22596). A. Branching pattern (meristematic zones shown by flexuous line). B. Filament showing meristematic regions and sessile plurilocular sporangia. C. Cells and sessile plurilocular sporangium. D–H. Feldmannia paradoxa (ADU, A31828). D. Branching pattern (meristematic zones shown by flexuous line). E. Branch system with meristematic zones and pedicellate plurilocular and unilocular sporangia. F. Young (upper) and mature (lower) cells. G. Plurilocular sporangium. H. Unilocular sporangium.

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