Electronic Flora of South Australia Genus Fact Sheet
Phylum Phaeophyta – Order Dictyotales – Family Scoresbyellaceae
Thallus erect, 6–19 cm long, complanate, dichotomous and becoming laterally branched, attached by a rhizoidal holdfast. Growth by a single, lenticular, apical cell in an apical depression of each branch, segmenting laterally on two sides. Fronds linear or increasing slightly in width above, apices broad. Structure 3 cells thick close to the apices, with a layer of large medullary cells and a single (becoming double) outer layer; mid thallus with a large central layer of medullary cells, two or three irregular layers of smaller medullary cells, and a cortical layer of small, densely phaeoplastic cells; older thallus 8–10 cells thick, grading from the small, cortical cells to larger inner medullary cells with the central layer largest. Hair tufts phaeophycean, scattered, developed from cortical cells.
Reproduction: Sporangial and oogonial plants unknown. Antheridial plants with scattered sori developed from cortical cells and surrounded by sterile, elongate paraphyses.
Type and only species: S. profunda Womersley.
Taxonomic notes: This distinctive genus is discussed above where it is placed in its own family of the Dictyotales, and the development of the thallus is described below in detail for the species.
References: The Marine Benthic Flora of Southern Australia Part II
Womersley, H.B.S. (14 December, 1987)
The Marine Benthic Flora of Southern Australia
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State Herbarium of South Australia