Electronic Flora of South Australia Species Fact Sheet

Percursaria percursa (C. Agardh) Rosenvinge.

Phylum Chlorophyta – Order Ulvales – Family Ulvaceae

Selected citations: Bliding 1963, 20, figs 5, 6. Davey & Woelkerling 1980: 57. Kornmann 1956: 259, figs 1–7.

Thallus (Fig. 42A) of entangled, loose-lying or floating masses of unbranched filaments to several cm long, 24–32 µm broad and 14–18 µm thick, uniseriate at first but mostly biseriate (Fig. 43A) and one cell thick (Fig. 43B), with the cells more or less paired. Cells square to slightly rectangular in surface view, 10–12 µm in diameter and (8–) 10–20 µm long; chloroplast usually occupying less than half of the cell with (1–) 2–3 pyrenoids.

Reproduction: Reproduction (Bliding 1963). Generations isomorphic, with quadriflagellate zoospores and biflagellate anisogametes; also by fragmentation.

Type from Hofmansgave, Denmark; in Herb. Agardh, LD, 13617.

Selected specimens: Redcliff Point, Spencer Gulf, S. Aust., mid eulittoral on Avicennia pneumatophores (Beanland, 9.iii.1981; LTB, 12197). Fawthrop Lagoon, Portland, Vic., in shallow water (Womersley, 29.xii.1981; ADU, A52859). Port Fairy, Vic. in shallow pool amongst samphires in a salt-marsh (van den Hoek, 2.ix1981; ADU, A5266 I-"Marine Algae of southern Australia" No. 215). Hovells Creek, Port Phillip, Vic., mid eulittoral on Avicennia pneumatophores ( Woelkerling, 12.viii.1977; LTB, 10205). Wallager Lake, N.S.W. (Cribb 80.11, 6.x.1950; ADU, A21053).

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

Distribution: Widely distributed on temperate and tropical coasts, usually in sheltered bays and inlets in the upper intertidal region.

Taxonomic notes: In southern Australia, from Tumby Bay, S. Aust. to Wallager Lake, N.S.W., associated with mangroves or samphires.

Percursaria is probably widely distributed on southern Australian coasts in shallow pools in sheltered areas such as samphire and mangrove communities.

The southern Australian material agrees well with the species, though the filaments are somewhat slenderer and the cells smaller than the dimensions given by Bliding (1963).


BLIDING, C. (1963). A critical survey of European taxa in Ulvales. Part I. Capsosiphon, Percursaria, Blidingia, Enteromorpha. Opera Bot. 8(3), 1–160.

DAVEY, A. & WOELKERLING, W.J. (1980). Studies on Australian mangrove algae. 1. Victorian communities: Composition and geographic distribution. Proc. R. Soc. Vict. 91, 53–66.

KORNMANN, P. (1956). Zur morphologie und entwicklung von Percursaria percursa. Helgoländer wiss. Meeresunters. 5, 259–272.

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

Author: H.B.S. Womersley

Publication: Womersley, H.B.S. (31 May, 1984)
The Marine Benthic Flora of Southern Australia
Part I
©Board of the Botanic Gardens and State Herbarium, Government of South Australia

Illustrations in Womersley Part I, 1984: FIGS 42A, 43A, B.

Figure 42 image

Figure 42   enlarge

Fig. 42. A. Percursaria percursa (ADU, A52661). B. Ulvaria oxysperma (ADU, A31812). C. Ulvaria shepherdii (ADU, A33006). D. Blidingia minima (ADU, A31811). E. Blidingia marginata (ADU, A21065).

Figure 43 image

Figure 43   enlarge

Fig. 43. A,B. Percursaria percursa (ADU, A52661). A. Biseriate filament, face view. B. Side view of filament. C,D. Ulvaria oxysperma (ADU, A31874). C. Cells near thallus margin. D. Lower part of thallus with cells developing attachment rhizoids. E–G. Ulvaria shepherdii (ADU, A33006). E. Cells in upper thallus. F. Lower cells with rhizoids. G. Cross section of thallus near base, with rhizoid producing cells. H,I. Blidingia minima (ADU, A53181). H. Cells in upper thallus. I. Base of thallus. J,K. Blidingia marginata (ADU, A52990). J. Cells in upper thallus. K. Base of thallus.

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