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Electronic Flora of South Australia
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Electronic Flora of South Australia Genus Fact Sheet

Genus HORMOSIRA (Endlicher) Meneghini 1838: 368, nom. cons.

Phylum Phaeophyta – Order Fucales – Family Hormosiraceae

Thallus (5–) 10–20 (–30) cm long, of branched chains of moniliform vesicular segments (0.3–) 0.5–2 (–3) cm in diameter, fusiform to oblong to subspherical, joined by slender constrictions usually 1–2 mm in diameter; branching occasional to frequent, from near the apex of the segments, 2–4 (–7) branches from a segment; holdfast usually small, discoid. Growth from a group of four apical cells, intermittently active (forming the segments) and inactive (forming the constrictions). Structure with a filamentous medulla, loose adjacent to the air space, a cortex of isodiametric cells, and an outer phaeoplastic meristoderm.

Reproduction: Plants dioecious, with conceptacles scattered over the vesicular segments; oogonia sessile, producing four eggs; antheridia on branched paraphyses.

Type species: H. moniliformis (Labillardière) Meneghini [= H. banksii (Turner) Decaisne].

Taxonomic notes: Although some 6 specific names have been applied within Hormosira, all are regarded as forms (largely ecoforms) of the one species, for which H. banksii is the earliest legitimate name. The development of the thallus and reproductive structures in an unnamed form have been described by Clayton et al. (1985).


CLAYTON, M.N., HALLAM, N.D., LUFF, S.E. & DIGGINS, T. (1985). Cytology of the apex, thallus development and reproductive structures of Hormosira banksii (Fucales, Phaeophyta). Phycologia 24, 181–190.

MENEGHINI, G. (1838). Cenni sulla organografia e fisiologia delle alghe. Atti R. Accad. Sci. Lett. Arti Padova 4, 325–388.

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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