Electronic Flora of South Australia Genus Fact Sheet

Genus SARCONEMA Zanardini 1858: 256

Phylum Rhodophyta – Class Florideophyceae – Order Gigartinales – Family Areschougiaceae

Thallus erect, regularly subdichotomously branched. Branches terete, slender, linear throughout; holdfast discoid and stoloniferous. Structure multiaxial, with a narrow medullary core of compact longitudinal filaments and a broad pseudoparenchymatous cortex of large inner cells with numerous secondary pit-connections and an outer cortex of small cells.

Reproduction: Sexual thalli probably dioecious; non-procarpic. Carpogonial branches 3 (–4) -celled, borne on a cortical cell 3–4 cells deep, directed inwards or laterally with a reflexed trichogyne, when fertilized producing a single, non-septate but often branched connecting filament. Auxiliary cell an inner cortical cell, not distinguishable before diploidization, producing a small-celled nutritive tissue towards the thallus surface and then a gonimoblast initial inwardly. Fusion cell large and irregular, with numerous arms at first inward but becoming radial, which cut off short chains of carposporangia, forming a globular carposporophyte; enveloping tissue absent but outer cortex extending as the pericarp outside the carposporophyte and becoming ostiolate. Spermatangia unknown.

Tetrasporangia scattered in the outer cortex, cut off laterally, zonately divided.

Life history triphasic with isomorphic gametophytes and tetrasporophytes.

Type species: S. furcellatum Zanardini 1858: 264 [= S. filiforme (Sonder) Kylin]

Taxonomic notes: A genus of two species (Papenfuss & Edelstein 1974) mainly of subtropical distribution, differing from Solieria in its regularly dichotomous, firm thallus, narrow medullary core of longitudinal filaments with a broad cortex many cells thick, and lack of any enveloping tissue.

The reproductive details given by Papenfuss & Edelstein (1974) apply mostly to S. scinaioides Boergesen, rather than the type species.

References:

PAPENFUSS, G.F. & EDELSTEIN, T. (1974). The morphology and taxonomy of the red alga Sarconema (Gigartinales, Solieriaceae). Phycologia 13, 31–44.

ZANARDINI, G. (1858). Plantarum in marl ntbro hucusque collectorum enumeratio. Mem. R. 1st. Veneto Sci. Lett. Arti 7, 209–309, Plates 3–14.

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.


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