Electronic Flora of South Australia Genus Fact Sheet
Phylum Rhodophyta – Class Florideophyceae – Order Gigartinales – Family Dumontiaceae
Thallus erect, much branched, branches terete, mucilaginous. Structure uniaxial, with whorls of four periaxial cells producing several orders of cells with a medulla becoming densely rhizoidal and a compact cortex of 4–5 layers of small cells, the outermost bearing a tomentum of acicular, thick-walled, hyaline hairs as well as normal hairs.
Reproduction: Sexual thalli dioecious, carpogonial and auxiliary cell branches scattered, borne on periaxial and inner medullary cells. Carpogonial branches 5–6 cells long, carpogonium reflexed and fusing post-fertilization with a lower cell, then producing connecting filaments. Auxiliary cell branches 12–15 cells long, the auxiliary cell 3–5 cells from the apex. Carposporophytes prominent, swelling the thallus, with a large basal fusion cell and each gonimoblast cell becoming a carposporangium. Spermatangia cut off from outermost cortical cells.
Tetrasporangia zonately divided, prominent, borne on inner cortical cells.
Life history triphasic with isomorphic gametophytes and tetrasporophytes.
Type (and only) species: D. insignis Montagne 1842: 8.
Taxonomic notes: Dasyphloea is characterised by the uniaxial thallus, compact cortex bearing prominent acicular hairs, carpogonial and auxiliary cell branches without lateral cells, and by the zonate tetrasporangia on isomorphic tetrasporophytes.
MONTAGNE, C. (1842). Prodromus Generum Specierumque Phycearum Novarum in Itinere ad Polum Antarcticum. (Paris.)
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.)
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