Electronic Flora of South Australia Species Fact Sheet
Phylum Rhodophyta – Class Florideophyceae – Order Gigartinales – Family Halymeniaceae
Reproduction: Sexual thalli monoecious. Carpogonial branch ampullae in the mid cortex, with 2–5-celled secondary branches and 2-celled carpogonial branches. Auxiliary cell ampulla similarly situated but more branched. Carposporophytes with several gonimolobes and slight involucre, immersed in the medulla, ostiolate. Spermatangia in small patches on the outer cortex.
Tetrasporangia scattered in the cortex, cruciately divided.
Type from the Mediterranean; in MA.
Selected specimens: Ocean Reef Marina, Perth., W. Aust., 6 m deep (O'Brien & Millar, 9.xii.1980; MELU, A39486; AD, A61638, female). Esperance, W. Aust., drift (Firman, Dec. 1952; AD, A18945, tetrasporangial).
Distribution: Widespread in tropical and subtropic oceans, and southward to Point Peron on the West Australian coast, also known from Esperance, W. Aust.
Taxonomic notes: Thallus rose-red to medium red, 10–40 cm high, mucilaginous, complanately much branched for 4–5 orders; axes 1–3 cm broad, laterals (2–) 5–10 mm broad, tapering to acute apices. Holdfast discoid, 2–5 mm across; epilithic or on mollusc shells. Structure of a relatively thin cortex 3–5 cells broad, with outer anticlinal filaments, inner cells ovoid and becoming stellate; medulla with most filaments transverse, refractive ganglionic cells present.
Subsp. floresia is known from sexual plants from Point Peron north, but from only a single tetrasporangial plant from southern Australia (from Esperance).
References: The Marine Benthic Flora of Southern Australia Part IIIA
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.
Illustration in Womersley Part IIIA, 1994: FIG. 56A.
Figure 56 enlarge
Fig. 56. A. Halymenia floresia subsp. floresia (AD, A18945). Transverse section of thallus with tetrasporangia. B. Halymenia floresia subsp. harveyana (AD, A60292). Transverse section of thallus with bisporangia. C–F. Halymenia kraftii (C, AD, A41636; D, AD, A60297; E, AD, A60468; F, AD, A61374). C. Carpogonial branch ampulla. D. Auxiliary cell ampulla, spread laterally. E. Transverse section of cortex with spermatangia. F. Transverse section of cortex with tetrasporangia.
State Herbarium of South Australia