Electronic Flora of South Australia Species Fact Sheet
Phylum Chlorophyta – Order Derbesiales – Family Bryopsidaceae
Selected citations: Womersley 1956: 363.
B. gracilis Sonder 1845: 49; 1846: 152.
Thallus (Fig. 95A,B) 4–10 (–15) cm high, bushy and very densely branched with 3 (–4) orders of branching, with few to numerous axes arising from a much branched, extensive, rhizoidal basal system, epilithic or epiphytic on Posidonia. Axes irregularly and densely branched above with some laterals strongly developed and basally denuded (Fig. 94E); young axes and laterals narrowly lanceolate in outline; branching of axes and laterals essentially radial but on plants epiphytic on Posidonia and Heterozostera branching on some older axes tending to be limited to opposite sides of the axes (Fig. 95B) but irregularly placed. Axes (300–) 400–1000 µm in diameter; main laterals 300–500 µm in diameter, lesser laterals 1–4 mm long, 100–200 µ in diameter; ramuli (0.2–) 0.5–1 mm long, (50–) 75–100 (–125) in diameter, upwardly curved and slightly tapering; scars on laterals prominent (Fig. 94E).
Reproduction: Reproduction unknown.
Type from Western Australia (Preiss, probably near Fremantle); holotype in MEL, 26486.
Selected specimens: Point Peron, W. Aust., low eulittoral on platforms (Womersley, 29.ix.1979; ADU, A50704-"Marine Algae of southern Australia" No. 228). Point Peron, W. Aust., uppermost sublittoral on Amphibolis (Womersley, 29.ix.1979; ADU, A50703-"Marine Algae of southern Australia" No. 228a). Whitfords Beach, Perth, W. Aust., 5 m deep on Heterozostera (Kirkman, 16.viii.1979; ADU, A50570). Hamelin Bay, W. Aust., drift (Womersley, 1.ix.1979; ADU, A50602).
Distribution: Apparently limited to the coast from Whitfords Beach to Hamelin Bay, and on Rottnest I., W. Aust., on rock platforms at low tide level and on Posidonia, Amphiholis and Heterozostera in shallow water.
Taxonomic notes: Bryopsis gracilis Sonder (holotype in MEL, 26487) appears to be only a small, relatively slender, form of B. foliosa and shows similar branching and dimensions. Since Sonder (1846) gave the same number for both names, they were presumably from the same collection and habitat.
B. foliosa appears to be a distinctive species with dense, radial branching, especially of the upper parts. Branching of plants on rough-water rock platforms (the type form) is entirely radial, but some specimens on Posidonia in more sheltered habitats (e.g. at Point Peron) have the laterals on lower parts of the axes more or less on two sides but still irregularly arranged. These are provisionally placed under B. foliosa.
In having largely radial branching, B. foliosa shows relationship to B. vestita, but the former is more densely branched and often with numerous strongly developed laterals, whereas B. vestita has numerous long axes from a common base.
The occasional restriction of laterals to opposite sides of the axes (in the epiphytic form on seagrasses) shows relationship to B. australis, with which there may well be gene interchange, and also to B. gemellipara from eastern southern Australia (see under the latter species). B. foliosa and B. australis occur in similar habitats in Western Australia.
Although only known on the west coast of Western Australia, as far south as Hamelin Bay, B. foliosa is included here for comparison with other species both in Western Australia and on southern coasts. This and the other Western Australian species need detailed morphological, reproductive and life history studies to clarify their relationships.
SONDER, O.W. (1845). Nova algarum genera et species quas in itinere ad oras occidentales Novae Hollandiae, collegit L. Preiss, Ph.Dr. Bot. Ztg 3, 49–57.
SONDER, O.W. (1846). Algae. In C. Lehmann, Plantae Preissianae. Vol. 2, pp. 148–160. (Hamburg.)
WOMERSLEY, H.B.S. (1956). A critical survey of the marine algae of southern Australia. I. Chlorophyta. Aust. J. mar. freshw. Res. 7, 343–383.
The Marine Benthic Flora of Southern Australia Part I complete list of references.
Womersley, H.B.S. (31 May, 1984)
The Marine Benthic Flora of Southern Australia
©Board of the Botanic Gardens and State Herbarium, Government of South Australia
Illustrations in Womersley Part I, 1984: FIGS 94E, 95A,B.
Figure 94 enlarge
Fig. 94. A,B. Bryopsis minor (ADU, A54041). A. Branching system. B. Chloroplasts with starch plates surrounding indistinct pyrenoids (upper from ramuli, lower from axes). C,D. Bryopsis macraildii. C. Branching (ADU, A50706). D. Upper branch (ADU, A5782). E. Bryopsis foliosa. Axes with laterals and ramuli (ADU, A50704).
Figure 95 enlarge
Fig. 95. A. Bryopsis foliosa (ADU, A50704). B. Bryopsis foliosa (ADU, A50703). C. Bryopsis vestita (ADU. A37734).
State Herbarium of South Australia