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Electronic Flora of South Australia Genus Fact Sheet

Genus CHOREONEMA Schmitz 1889: 455

Phylum Rhodophyta – Class Florideophyceae – Order Corallinales – Family Corallinaceae – Subfamily Choreonematoideae

Thallus largely unconsolidated, vegetative portions endophytic but conceptacles produced external to the host. Structure filamentous to partly pseudoparenchymatous; organisation vaguely dorsiventral; construction diffuse, consisting of short, simple or branched endophytic filaments that may become partially consolidated in areas of conceptacle production but collectively lack any regularised internal structure; cell elongation characteristics uncertain; cell-fusions, secondary pit-connections, epithallial cells, haustoria and trichocytes unknown.

Reproduction: Vegetative reproduction unknown. Gametangia and tetrasporangia formed in uniporate, calcified conceptacles produced external to the host, roofs composed of a single layer of cohering filaments. Bisporangia unknown.

Gametangial thalli dioecious. Carpogonia terminating 2- or 3-celled filaments arising from the female conceptacle chamber floor. Carposporophytes composed of a central fusion cell and several-celled gonimoblast filaments bearing terminal carposporangia. Spermatangial filaments unbranched, produced on floor, walls and roof of male conceptacle chambers.

Tetrasporangia scattered across the conceptacle chamber floor, roofs arising from filaments peripheral to the sporangial initials, each mature sporangium containing zonately arranged tetraspores and possessing an apical plug that helps to block the roof pore prior to spore release.

Type species: C. thuretii (Bornet in Thuret & Bornet)Schmitz 1889: 455. Basionym: Melobesia thuretii Bornet in Thuret & Bornet 1878: 96.

Taxonomic notes: Choreonema contains one species. Endosiphonia Ardissone 1883 (non Zanardini 1878) is an older but illegitimate name for Choreonema. Details relating to generic etymology, nomenclature, synonymy and infrageneric classification are provided by Woelkerling (1988, pp. 90, 91). The following account is based mainly on data in Woelkerling (1987a).

References:

ARDISSONE, F. (1883). Phycologia mediterranea. Part 1. Floridée. Memorie Soc. Crittogam. Ital. 1, 1–516.

SCHMITZ, F. (1889). Systematische Ubersicht der bisher bekannten Gattungen der Florideen. Flora, Jena 72, 435–456, Plate 21.

THURET, G. & BORNET, E. (1878). Études Phycologiques. (G. Masson: Paris.)

WOELKERLING, W.J. (1987a). The genus Choreonema in southern Australia and its subfamilial classification within the Corallinaceae (Rhodophyta). Phycologia 26, 111–127.

WOELKERLING, Wm.J. (1988). The Coralline Red Algae. [British Museum (N.H.): London.]

ZANARDINI, G. (1878). Phyceae Papuanae novae vel minus cognitae a cl. Beccari in itinere ad Novam Guineam annis1872–75 collectae. Nuovo Giornale Botanica Italiano 10, 34–40.

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

Author: W.J. Woelkerling

Publication: Womersley, H.B.S. (28 June, 1996)
The Marine Benthic Flora of Southern Australia
Rhodophyta. Part IIIB. Gracilarialse, Rhodymeniales, Corallinales and Bonnemaisoniales
Reproduced with permission from The Marine Benthic Flora of Southern Australia Part IIIB 1996, by H.B.S. Womersley. Australian Biological Resources Study, Canberra. Copyright Commonwealth of Australia.


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