Electronic Flora of South Australia Genus Fact Sheet
Phylum Rhodophyta – Class Florideophyceae – Order Gigartinales – Family Dumontiaceae
Thallus (gametophyte) erect, subdichotomous from a prostrate base (around the stems of Amphibolis); branches slightly compressed, tapering slightly. Structure multiaxial with a filamentous medulla and compact cortex with surface hairs.
Reproduction: Sexual thalli monoecious, with carpogonial and auxiliary cell branches scattered in outer medulla. Carpogonial branches 9–12 cells long with carpogonium reflexed, cells 4 and 5 larger and densely cytoplasmic, and single sterile lateral cells on lower cells; post-fertilization fusion between the carpogonium and cell 4 produces an enlarged fusion cell from which several connecting filaments develop. Auxiliary cell branches 9–14 cells long, with the auxiliary cell 4 or 5 cells from the apex and adjacent cells forming short lateral branches. Carposporophytes developing 3–4 groups of gonimoblast cells, then becoming globular, with most cells forming carposporangia, scattered in outer medulla and not distending the cortex. Spermatangia cut off from outer cortical cells.
Tetrasporophyte crustose on Amphibolis stems, with zonate tetrasporangia.
Life history triphasic with heteromorphic erect gametophytes and crustose tetrasporophytes.
Type (and only) species: K. dichotoma Shepley & Womersley 1983: 209.
Taxonomic notes: Kraftia and Gibsmithia are the only multiaxial genera of the Dumontiaceae in southern Australia, and differ in habit (Kraftia subdichotomous from the holdfast on Amphibolis, Gibsmithia with a cartilaginous basal stalk and upper gelatinous irregular branches) and in that Gibsmithia has isomorphic gametophytes and tetrasporophytes while in Kraftia gametophytes are erect and the genus is heteromorphic with a crustose tetrasporophyte.
SHEPLEY, E.A. & WOMERSLEY, H.B.S. (1983). The Dumontiaceae (Cryptonemiales: Rhodophyta) of southern Australia. Trans. R. Soc. S. Aust. 107, 201–217.
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