|
|
|
|
|
|||||||||||
|
Electronic Flora of South Australia Species Fact Sheet
Phylum Rhodophyta – Class Florideophyceae – Order Gigartinales – Family Peyssonneliaceae
Thallus yellow-red to red-brown, rounded and 1–6 cm across or under wave flow extending as elongate patches 5–30 cm long and 3–10 cm across, completely adherent to rock and with an even margin and irregular radial streaks; 160–400 (–500) µm thick. Structure. Basal layer (Fig. 46G) of radiating lines of cells or vague flabellules, each cell 8–16 µm in diameter and L/D 1.5–2.5, producing short unicellular rhizoids from the lower side of occasional cells; hypobasal calcification present. Erect filaments (Fig. 46E, F) assurgent at 50–80°, 15–30 cells long, with the lowest cell of similar dimensions to the cells of the basal layer but more erect (14–20 µm diameter and L/D 1.2–2) and centrally pit-connected to it, then branching from 1–4 lower cells and occasional upper cells, becoming 4–8 µm in diameter with cells L/D 1–2 for many rows below the surface; surface cells mostly not in rows; cystoliths (Fig. 46C, D) usually present in dense and extensive clusters in lower to mid parts of young thalli, forming oval patches (as seen from the surface) 1–4 cells thick, sometimes rare in some areas of thalli and in older thalli; on decalcification such cystolith cells are usually elongate and distinct .
Reproduction: Sexual plants unknown.
Tetrasporangial nemathecia (Fig. 4614) inconspicuous, low, 0.5–1.5 mm across, scattered; paraphyses modified from upper thallus cells, 60–80 µm and 6–8 cells long; tetrasporangia (Fig. 46I) 50–80 µm long and 20–30 µm in diameter, decussately cruciately divided.
Type from Wanna (W of Port Lincoln), S. Aust., uppermost sublittoral (Womersley, 15.i.1987); holotype in AD, A57377.
Distribution: Cape Carnot, S. Aust., to Flinders, Vic.
Taxonomic notes: P. splendens is a striking species and probably the most expansive of the completely adherent ones; the colour and form are distinctive, as are the extensive patches of closely grouped cystoliths and the shallow nemathecia. The type material from Wanna occurred on smooth rock just below low tide level under strong wave wash, and extended lengthwise in slight depressions where water streams down the rock after waves at very low tide. Cystolith clusters were present in some parts of the young thallus but not in other regions. The Abalone Cove collections had more abundant sheets of cystoliths. The basal layer in the type was essentially of parallel filaments, but in smaller specimens from Abalone Cove small flabellules were present near the margins.
The tetrasporangial nemathecia consist of only very slightly raised patches with tetrasporangia lying among upper thallus filaments which are only a few cells longer than the upper vegetative filaments; this situation is similar to P. immersa Maggs & Irvine (1983) from Britain, but the tetrasporangia are terminal on paraphyses in the latter.
P. splendens differs from other species of similar habit and structure [e.g. P. meridionalis Hollenberg & Abbott (1968, p. 1244) and P. hairii Hollenberg & Abbott (1968, p. 1244) from California] in possessing grouped cystoliths (though Maggs & Irvine 1983, p. 230 state the thallus of P. meridionalis is slightly calcified, in contrast to the original description) and also in the size and form of tetrasporangia.
References:
HOLLENBERG, G.J. & ABBOTT, I.A. (1968). New species of marine algae from California. Can. J. Bot. 46, 1235–1251.
MAGGS, C.A. & IRVINE, L.M. (1983). Peyssonnelia immersa sp. nov. (Cryptonemiales, Rhodophyta) from the British Isles and France, with a survey of infragenic classification. Br. phycol. J. 18, 219–238.
The Marine Benthic Flora of Southern Australia Part IIIA complete list of references.
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.
Illustration in Womersley Part IIIA, 1994: FIG. 46 C–I.
Figure 46 enlarge
Fig. 46. A, B. Peyssonnelia foliosa (A, AD, A59300; B, AD, A58662). A. RVS of thallus with two cystoliths, rhodoplasts shown in one basal cell, and tetrasporangia. B. Section of a female nemathecium, with rows of carposporangia from 3 carposporophytes (two carposporangia stippled to show rhodoplasts). C–I. Peyssonnelia splendens (C, D, G, AD, A60021; E, F, H, I, AD, A57377). C. Section of thallus showing regions of clustered cystoliths and patches of hypobasal calcification. D. Detailed sectional view of clustered cystoliths. E. RVS of growing apex of thallus. F. RVS of mature thallus. G. Branching pattern of basal layer. H. Diagrammatic view of RVS with tetrasporangial nemathecium. I. Tetrasporangia and paraphyses.
|
Email Contact: State Herbarium of South Australia |
|
