Electronic Flora of South Australia Genus Fact Sheet
Phylum Rhodophyta – Class Florideophyceae – Order Nemaliales – Family Galaxauraceae
Thallus (gametophyte) erect, simple or terete to compressed and furcately branched or proliferous, often becoming hollow, with a loose filamentous medulla and a relatively compact cortex of small-celled anticlinal filaments. Not calcified. Rhodoplasts discoid to elongate, few per cell.
Tetrasporophyte crustose, discoid, with a basal layer producing erect filaments.
Reproduction: Carpogonial branches 3–4-celled, borne on inner cortical filaments with the hypogynous and basal cells producing short lateral branches. Gonimoblast developing from the fertilized carpogonium, branched, with terminal carposporangia, surrounded by a dense involucre of sterile filaments developed from the sub-carpogonial cells and forming an ostiolate cystocarp. Spermatangia cut off from filaments within surface pits (Martin 1936).
Life history triphasic with heteromorphic gametophyte and tetrasporophyte.
Type species: N. variolosa (Montagne) Montagne 1843: 302 [=?N. fastigiata (Bory) Parkinson].
Taxonomic notes: The tetrasporophyte reproducing by cruciately divided tetrasporangia borne laterally on the erect filaments of the crust.
A genus of about 5 species in southern hemisphere cool temperate and subantarctic waters, with one species reaching south-east Australia.
Parkinson (1983) reviewed the confusion over the name Chaetangium Kützing, which Papenfuss (1952, p. 173) had shown was based on a plant now referred to Suhria vittata, and adopted the earliest correct name of Nothogenia. Other Australian species previously ascribed to Chaetangium are C. corneum J. Agardh which is now Adelophycus corneus (J. Agardh) Kraft and C. flabellatum Harvey which is Polyopes constrictus (Turner) J. Agardh.
The type species of Nothogenia, N. variolosa from the Auckland Is, as illustrated by Montagne (1845, fig. 3) is a much branched plant with narrow branches. Chapman (1969, p. 70) comments on the extreme variability of the New Zealand taxon, and Ricker (1987, p. 168) also doubts whether this material (and the type of N. variolosa) is the same as N. fastigiatum from the Falkland Is and other subantarctic islands; clearly further study is needed.
CHAPMAN, V.J. (1969). The marine algae of New Zealand. Part III: Rhodophyceae. Issue 1: Bangiophycidae and Florideophycidae (Némalionales, Bonnemaisoniales, Gélidiales). (Cramer: Germany.)
MARTIN, M.T. (1936). The structure and reproduction of Chaetangium saccatum (Lam.)J. Ag. - I. Vegetative structure and male plants. Proc. Linn. Soc. Lond., Session 148, 165–181, Plate 10.
MONTAGNE, C. (1843). Quatrième centurie de plantes cellulaires exotiques nouvelles. Ann. Sci. Nat. 2 Sér. Bot. 20, 294–306.
MONTAGNE, C. (1845). Voyage au Pôle Sud et dans l'Océanie sur les Corvettes l'Astrolabe et la Mee. Botanique, T I. Plantes cellulaires. (Plates 1–20 dated 1852.)
PAPENFUSS, G.F. (1952). Notes on South African marine algae III. J. S. Afr. Bot. 17, 167–188.
PARKINSON, P.G. (1983). The typification and status of the name Chaetangium (algae). Taxon 32, 605–610.
RICKER, R.W. (1987). Taxonomy and biogeography of Macquarie Island Seaweeds. [British Museum (N.H.): London.]
The Marine Benthic Flora of Southern Australia Part IIIA complete list of references.
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.
State Herbarium of South Australia