Electronic Flora of South Australia Genus Fact Sheet

Genus STENOCLADIA J. Agardh 1872: 44

Phylum Rhodophyta – Class Florideophyceae – Order Gigartinales – Family Nizymeniaceae

Thallus erect, marginally or subdichotomously branched from strongly compressed or terete branches; holdfast discoid. Structure uniaxial with three or four periaxial cells and the axial filament remaining conspicuous throughout the thallus, surrounded by a dense rhizoidal medulla and a pseudoparenchymatous cortex of close-fitting angular cells.

Reproduction: Sexual thalli probably dioecious. Procarps in tufts of filaments on the thallus margin or surface, with one to three 3-celled carpogonial branches and an associated auxiliary cell. Carposporophyte with a conspicuous fusion cell and dense, radiating, gonimoblast filaments with short, terminal, chains of carposporangia, within a globular, protruding and basally constricted cystocarp with a thick ostiolate pericarp. Spermatangia borne on branched laterals of uniseriate filaments in tufts on the thallus surface.

Tetrasporangia (little known) borne on branched uniseriate filaments in tufts on the thallus surface, probably cruciately divided.

Life history triphasic with isomorphic gametophytes and tetrasporophytes.

Lectotype species: S. conferta (Harvey) J. Agardh 1872: 45. [= S. australis (Sonder) Silva.]

Taxonomic notes: Stenocladia differs from Nizymenia in having a conspicuous axial filament throughout the thallus.

References:

AGARDH, J.G. (1872). Bidrag till Florideernes Systematik. Acta Univ. hind. 8, 1–60.

The Marine Benthic Flora of Southern Australia Part IIIA complete list of references.

Author: H.B.S. Womersley

Publication: Womersley, H.B.S. (14 January, 1994)
The Marine Benthic Flora of Southern Australia
Rhodophyta. Part IIIA, Bangiophyceae and Florideophyceae (to Gigartinales)
Reproduced with permission from The Marine Benthic Flora of Southern Australia Part IIIA 1994, by H.B.S. Womersley. Australian Biological Resources Study, Canberra. Copyright Commonwealth of Australia.

KEY TO SPECIES OF STENOCLADIA

1. Thallus branches compressed; cystocarps marginal

S. australis

1. Thallus branches terete; cystocarps on all sides

S. furcata


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