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Genus DELISEA Lamouroux 1819: 41

Phylum Rhodophyta – Class Florideophyceae – Order Bonnemaisoniales – Family Bonnemaisoniaceae

Thallus erect, much branched essentially complanately with compressed axes and alternate, terete to compressed and spinous, distichous, simple or branched ramuli; holdfast discoid. Structure uniaxial with a small apical cell, subapical cells each cutting off two pairs of periaxial cells, each pair developing lateral and transverse periaxial filaments, the first formed lateral filaments developing the alternate ramuli, the second lateral filament extending to the sinus between ramuli, and the transverse filaments contributing to the cortex. Branches with a prominent axial filament becoming surrounded by a sheath of small-celled rhizoidal filaments, and a large-celled inner and small-celled outer cortex; cortical gland cells absent or present.

Reproduction: Gametangial thalli monoecious or dioecious. Carpogonial branches 3-celled, borne on lower cells of the shorter of the lateral periaxial filaments, with a basal fusion cell producing a tuft of branched gonimoblast filaments with terminal carposporangia, and with a group of darker staining nutritive filaments (probably from the hypogynous cell) at the base of the carposporophyte. Cystocarps immersed in the swollen branch cortex between two ramuli, with a relatively thick pericarp, ostiolate. Spermatangial sori covering parts of the ramuli or lesser branches.

Tetrasporangia (where known) in raised nemathecia on upper branches, among elongate-clavate paraphyses, obliquely divided, or probably in small discoid crusts (Bonin & Hawkes 1988a).

Life history triphasic with isomorphic gametophytes and tetrasporophytes (known in D. pulchra and D. plumosa), or with heteromorphic crustose tetrasporophytes.

Lectotype species: D. elegans Lamouroux (see Silva 1957, p. 143)

Taxonomic notes: A genus of 6 species, four from southern Australia, four from New Zealand (3 Australian also) and one from Japan.

Delisea differs from Ptilonia (with which it was united by Chihara & Yoshizaki 1978) in having the alternate lateral periaxial filaments developing into discrete ramuli (spinous in some species) whereas in Ptilonia the lateral periaxial filaments remain adherent to form the flat branches, with only small spines representing the ends of the filaments.


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.

CHIHARA, M. & YOSHIZAKI, M. (1978). Anatomical and reproductive features of Ptilonia okadai (Rhodophyta, Bonnemaisoniaceae). Phycologia 17, 382–387.

LAMOUROUX, J.V.F. (1819). Delisea. Dict. Sci. Nat. (Levrault) 13, 41–42.

SILVA, P.C. (1957). Remarks on algal nomenclature. Taxon 16, 141–145.

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. Ramuli terete, tapering gently from the base 100–200 µm in diameter


1. Ramuli compressed, tapering markedly from the base when young, 150–400 µm broad basally


2. Ramuli unbranched, 1–1.5 mm long, remaining regularly distichous, complanately branched

D. elegans

2. Ramuli simple or commonly with 1–3 branches, mostly 1–2 (–3) mm long, distichous only near the apices and becoming flexed below so that the frond is not complanately branched

D. hypneoides

3. Ramuli compressed throughout, with many between the indeterminate branches, without minute opposite ramuli; basal width 250–400 µm

D. pulchra

3. Indeterminate laterals usually separated by 4 ramuli, two on each side; often with minute opposite ramuli; ramuli becoming subterete, 1–2 (–3) mm long and 150–300 µm in basal width

D. plumosa

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