Electronic Flora of South Australia Species Fact Sheet

Delisea plumosa Levring 1955: 427, fig. 13.

Phylum Rhodophyta – Class Florideophyceae – Order Bonnemaisoniales – Family Bonnemaisoniaceae

Selected citations: Bonin & Hawkes 1988a: 627, figs 22,23. Chapman 1969: 83, pl. 22.

Thallus (Fig. 155A, B) dark red-brown, 12–30 cm high, complanately and regularly branched with alternate indeterminate branches separated by usually four (sometimes 2 or 6) determinate ramuli (Fig. 155B), evenly spaced with two on each side, alternating but with occasional to frequent very short spinous ramuli opposite the longer ones; ramuli mostly remaining on lower branches. Branches compressed, (300–) 500–700 µm broad above, 500–1000 (–1400) µm broad below, thickened to 1 mm near the base. Ramuli near branch apices compressed, tapering, 250–1000 (–1500) µm long and basally 100–250 µm broad, on lower branches becoming subterete, 1–2 (–3) mm long and basally 150–300 µm broad. Holdfast discoid, 1–2 mm across, bearing 1–3 fronds; epilithic. Structure uniaxial, the subapical cells with lateral and transverse periaxial cells, the lateral ones producing alternate ramuli with some opposite periaxial filaments forming the very short spines. Branches 8–15 cells thick, the axial filament 35–60 µm in diameter, with a slight sheath of small cells, inner cortical cells ovoid, 40–100 µm in diameter, outer cortical cells angular in surface view, 4–8 µm across, with frequent, scattered, subsurface gland cells (Fig. 155C) with a rosette of outer cells. Rhodoplasts discoid, in chains in inner cells.

Reproduction: Gametangial thalli dioecious or monoecious. Carpogonial branches unknown. Carposporophyte (Fig. 155E) with a small basal fusion cell and a surrounding nutritive tissue, and a tuft of slender, branched, gonimoblast filaments with terminal, elongate-ovoid carposporangia 25–55 µm in diameter. Cystocarps (Fig. 155D) on the flat surface near branch ends, sessile, 500–900 µm across, with a thick pericarp and an ostiole directed forwards and outwards. Spermatangial sori (Fig. 155F) raised, often appearing pustular, near branch apices, with the outer cortical cells each cutting off several elongate initials and spermatangia 2–3 µm in diameter.

Tetrasporangial nemathecia (Fig. 155G) on upper branches or ramuli, 50–80 µm thick, with the outer cortical cells producing elongate-clavate unicellular paraphyses and ovoid to clavate tetrasporangia (Fig. 155H) 40–60 µm long and 15–25 µm in diameter, obliquely divided.

Type from Stewart I., New Zealand (Lindauer, 7.i.1946); holotype in Herb, Levring, Goteborg (Levring 1955, fig. 13).

Distribution map based
on current data relating to
specimens held in the
State Herbarium of SA

Distribution: Stewart I. and Otago, N.Z. SE and SW Tasmania.

Taxonomic notes: The Tasmanian specimens agree very well in habit and structure with isotypes in AD (Lindauer 6937 and Alg. Nova-Zel. Exsicc. 192); A58490 and Kraft 9327 are tetrasporic while AD, A63353 is sexual. They are superficially similar to D. elegans but the latter has terete ramuli with irregular numbers of ramuli between the indeterminate lateral branches, and lacks the occasional minute ramuli opposite the normal ramuli in D. plumosa. The specimens from Scotts Point have an apparent pulvinate parasite.

References:

BONIN, D.R. & HAWKES, M.W. (1988a). Systematics and life histories of New Zealand Bonnemaisoniaceae (Bonnemaisoniales, Rhodophyta): H. The genus Delisea. N.Z. J. Bot. 26, 619–632.

CHAPMAN, V.J. (1969). The marine algae of New Zealand. Part III: Rhodophyceae. Issue 1: Bangiophycidae and Florideophycidae (Nemalionales, Bonnemaisoniales, Gélidiales), pp. 1–113, Plates 1–38. (Cramer: Germany.)

LEVRING, T. (1955). Contributions to the marine algae of New Zealand. I. Rhodophyta: Goniotrichales, Bangiales, Nemalionales and Bonnemaisoniales. Arkiv för Bot. Ser. 2, 3, 407–432.

The Marine Benthic Flora of Southern Australia Part IIIB complete list of references.

Author: H.B.S. Womersley

Publication: Womersley, H.B.S. (28 June, 1996)
The Marine Benthic Flora of Southern Australia
Rhodophyta. Part IIIB. Gracilarialse, Rhodymeniales, Corallinales and Bonnemaisoniales
Reproduced with permission from The Marine Benthic Flora of Southern Australia Part IIIB 1996, by H.B.S. Womersley. Australian Biological Resources Study, Canberra. Copyright Commonwealth of Australia.

Illustration in Womersley Part IIIA, 1996: FIG. 155.

Figure 155   enlarge

Fig. 155. Delisea plumosa (A, B, D–F, AD, A63353; C, AD, A58491; G, H, AD, A58490). A. Habit. B. Branches showing arrangement of laterals and ramuli. C. Surface view of branch with gland cells. D. Branches with cystocarps. E. Section of a cystocarp with carposporophyte. F. Transverse section of a branch with spermatangial sorus on left. G. Branch with tetrasporangial sorus. H. Transverse section of branch with a tetrasporangial sorus.

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