Electronic Flora of South Australia Family Fact Sheet
Thallus massive, usually 1–15 m long, with a large, thick, discoid holdfast usually 10–25 cm across, a thick stipe, and laciniate or laterally branched flattened fronds; branching usually largely in the one plane. Structure haplostichous, with an internal filamentous medulla (solid or honeycombed) with sieve tube-like elements, and an outer cortex of many layers of isodiametric cells with a surface meristoderm. Growth diffuse throughout most of the thallus but predominately towards the ends of branches. Phaeoplasts 2 (–3) per cell, discoid to elongate, without pyrenoids.
Reproduction: Thalli dioecious, with conceptacles scattered over the fronds, fertile in winter. Oogonia and antheridia borne within conceptacles, on branched paraphyses or sessile (oogonia of some species); oogonia containing 4 eggs, antheridia with 64 sperms.
Life history diplontic, with meiosis at gametogenesis.
Taxonomic notes: This order includes the single, most distinctive, genus Durvillaea, found in cold temperate and subantarctic southern hemisphere waters, growing either in the lower eulittoral or upper sublittoral.
Durvillaea was earlier included in the Fucales as a separate family owing to its similar diplontic life history and conceptacles bearing oogonia or antheridia. However the diffuse growth with splitting or lateral outgrowths from the fronds, and the presence of oogonia on branched filaments in the conceptacles, warrant ordinal separation from the Fucales (Petrov 1965, p. 72; Nizamuddin 1968b; Clayton et al. 1987). Also, the mature thallus appears to be largely haplostichous in its development and structure (Naylor 1949b; Roberts 1979), though the young sporeling divides by intercalary longitudinal as well as transverse walls (Naylor 1953, fig. 12).
CLAYTON, M.N., HALLAM, N.D. & SHANKLY, C.M. (1987). The seasonal pattern of conceptacle development and gamete maturation in Durvillaea potatorutn (Durvillaeales, Phaeophyta). Phycologia 26, 35–45.
NAYLOR, M. (1949b). Observations on the anatomy of Durvillea antarctica (Chamisso) Hariot. Ann. Bot., N.S., 13, 285–308, Plates 6, 7.
NAYLOR, M. (1953). The New Zealand species of Durvillea. Trans. R. Soc. N.Z. 80, 277–297, Plates 58–61.
NIZAMUDDIN, M. (1968b). Observations on the order Durvilleales J. Petrov, 1965. Bot. Mar. 11, 115–117.
PETROV, J.E. (1965). De positione familiae Durvilleacearum et systematica classis Cyclosporophycearum (Phaeophyta). In Novitates Systematicae Plantarum non Vascularium, Inst. Bot. Acad. Sci. 1965, 70–72.
ROBERTS, M. (1979). Observations on cell structure and cytology in the genus Durvillaea Bory. N.Z. .1. Bot. 17, 241–249.
The Marine Benthic Flora of Southern Australia Part II complete list of references.
Womersley, H.B.S. (14 December, 1987)
The Marine Benthic Flora of Southern Australia
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State Herbarium of South Australia