Electronic Flora of South Australia Genus Fact Sheet

Genus HORMOPHYSA Kützing 1843: 359

Phylum Phaeophyta – Order Fucales – Family Cystoseiraceae

Thallus usually 10–40 cm long, with a short stipe from a discoid-conical holdfast, bearing several primary branches. Primary branches more or less straight, with triquetrous, interrupted, wings and similar laterals arising from the branch rhachis. Vesicles present within the primary and lateral branches, developed within the medulla, elongate. Growth from a single, three-sided, apical cell in an apical depression. Structure of a central medulla of elongate cells in the rhachis of branches, and an extensive cortex of isodiametric cells with a surface phaeoplastic meristoderm; cryptostomata scattered over the whole frond.

Reproduction: Conceptacles scattered over the whole thallus but best developed in walls of the vesicles and thicker parts, bisexual; oogonia with a single egg.

Type species: H. triquetra (C. Agardh) Kützing.

Taxonomic notes: Hormophysa is a monotypic genus (Papenfuss 1967), with several names having been applied to forms of the type species. It is characterised by the triquetrous wings, containing the conceptacles, on the branches, which also contain internal vesicles on the upper parts.


KÜTZING, F.T. (1843). Phycologia generalis. (Leipzig.)

PAPENFUSS, G.F. (1967). The history, morphology and taxonomy of Hormophysa (Fucales: Cystoseiraceae). Phytomorphology 17, 42–47.

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
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