Electronic Flora of South Australia Family Fact Sheet

ORDER NEMALIALES Schmitz in Engler 1892: 17

Phylum Rhodophyta – Class Florideophyceae

Thallus (gametophyte and also sporophyte in some Galaxauraceae) erect, 1–30 cm high, usually much branched irregularly or subdichotomously, branches terete to compressed, multiaxial with a filamentous medulla (becoming hollow in some Galaxauraceae) and an anticlinal filamentous or pseudoparenchymatous cortex; some taxa calcified; sporophytes minute, of discrete filaments, or crustose, or similar to gametophytes but dimorphic in Galaxaura. Cells uninucleate, rhodoplasts parietal, lobed to stellate, with or without pyrenoids. Growth of branches and of filaments apical.

Reproduction: Carpogonial branches 3- or 4-celled, lateral or terminal on cortical filaments, with the lower cells (hypogynous, basal or supporting cells) usually producing sterile filaments Jorming a loose to dense involucre. Gonimoblast filaments developing from the fertilized carpogonium, directly or after subdivision, producing carposporangia terminally, singly or in short chains; carposporophytes lying within the cortex or outer medulla, with or without a sterile involucre, cystocarps ostiolate or not. Spermatangia cut off from outer cortical cells or within conceptacles.

Tetrasporangia cruciately divided, borne on filamentous or crustose sporophytes or on erect sporophytes.

Life history triphasic, heteromorphic in Liagoraceae and more or less isomorphic but with gametophytes structurally dimorphic in Galaxaura.

Taxonomic notes: The above description includes two marine families, and regards the Acrochaetiales, Bonnemaisoniales and Gelidiales as separate orders.

References:

ENGLER, A. (1892). Syllabus der Vorlesungen über specielle and medicinisch-pharmaceutische Botanik ... Grosse Ausgabe. (Borntraeger: Berlin.)

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 FAMILIES OF NEMALIALES

1. Gonimoblast not surrounded by a distinct filamentous involucre (though in some with basal, loose, involucral filaments) and without a distinct ostiole

LIAGORACEAE

1. Gonimoblast surrounded by a distinct filamentous involucre, derived from the basal cell of the carpogonial branch or from gonimoblast filaments, cystocarps with a distinct ostiole

GALAXAURACEAE


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