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Genus BONNEMAISONIA C. Agardh 1822: 196

Phylum Rhodophyta – Class Florideophyceae – Order Bonnemaisoniales – Family Bonnemaisoniaceae

Thallus (gametophyte) erect, much-branched with long, terete to slightly compressed branches bearing opposite pairs of distichous (or spiral) branchlets, usually with a longer determinate branchlet opposite a short branchlet which often produces the sexual organs or develops further as a branch; attachment rhizoidal, discoid or by hamate branchlets, epiphytic or epilithic. Structure uniaxial, with small but prominent apical cells, the apical filament conspicuous throughout the thallus, with subapical cells producing opposite and distichous periaxial cells which develop the branchlets; cortication of the branches by the first periaxial cells each cutting off about 4 cortical cells (which may subdivide) which become relatively large, with two or more corresponding lengthwise to each axial cell and 6–8 around the branch, then cutting off small, rounded, outer cortical cells which often form rosettes, some developing darkly staining contents (gland or iodine cells); inner cortex separated by a "space" from the axial filament. Branchlets with axial cells cutting off 3 periaxial cells which develop a cortex as in the branches, with or without spines.

Tetrasporophytes filamentous, branched, tufted or prostrate.

Reproduction: Gametangial thalli monoecious or dioecious. Carpogonial branches 3-celled, borne on the subapical cell of short branchlets, with the hypogynous cell forming a tuft of nutritive filaments; following fertilization the carpogonium produces branched gonimoblast filaments with terminal carposporangia, a fusion cell develops by union of the cells of the carpogonial branch and adjacent cells, and the supporting cell and adjacent periaxial cells produce erect filaments which form the pericarp. Cystocarps pedicellate (on 5–8 axial cells), urceolate, ostiolate. Spermatangial organs shortly pedicellate, ovoid to elongate with a central row of 4–8 axial cells, each cutting off radially several periaxial filaments which form an outer layer of spermatangial initials and spermatangia.

Tetrasporophytes [known in, e.g. B. asparagoides (Hymenoclonium) and B. hamifera (Trailliella)] uniseriate, branched, tufted or prostrate, bearing lateral tetrasporangia, tetrahedrally or irregularly divided.

Life history triphasic, heteromorphic.

Lectotype species: B. asparagoides (Woodward) C. Agardh 1822: 197.

Taxonomic notes: A genus of about seven species, with two on southern Australian coasts. The structure and development of the female and male reproductive organs appears uniform in all species, with some differences in the heteromorphic tetrasporophytes (see Feldmann & Feldmann 1942, and Shevlin & Polanshek 1978) which are unknown for the southern Australian species. The type species has been studied in detail by Kylin (1916) and Svedelius (1933, p. 39, figs 43–48).

Bonnemaisonia is most closely related to Asparagopsis, differing in having distichous compared to radial branching, and in the pedicel of the cystocarp being 5–8 axial cells long compared to 9–11 cells (Hudson & Wynne 1969).


AGARDH, C.A. (1822). Species Algarum. Vol. 1, Part 2, pp. 169–398. (Berling: Lund.)

FELDMANN, J. & FELDMANN, G. (1942). Recherches sur les Bonnemaisoniacées et leur alternance de générations. Ann. Sci. Nat., Sér. 11 Bot. 3, 75–175.

HUDSON, P.R. & WYNNE, M.J. (1969). Sexual plants of Bonnemaisonia geniculata (Nemaliales). Phycologia 8, 207–213.

KYLIN, H. (1916). Die Entwicklungsgeschichte and die systematische Stellung von Bonnemaisonia asparagoides (Woodw.)Ag. nebst einigen Worten fiber den Generations wechsel der Algen. Zeitschr. f Bot 8, 545–586.

SHEVLIN, D.E. & POLANSHEK, A.R. (1978). Life history of Bonnemaisonia geniculata (Rhodophyta), a laboratory and field study. J. Phycol. 14, 282–289.

SVEDELIUS, N. (1933). On the development of Asparagopsis armata Harv. and Bonnemaisonia asparagoides (Woodw.)Ag. Nova Acta Reg. Soc. Sci. Upsal., Ser. IV, 9, 1–61.

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.


1. Spines absent; primary cortical 'cells not in tiers, subspherical with 2–4 covering the axial cell; rosettes of small secondary cortical cells present

B. australis

1. Spines present, of (4–) 5–6 (–9) cells; primary cortical cells forming two tiers per axial cell (spines on the first tier); rosettes slight, secondary cortical cells small and sparse

B. spinescens

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