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Genus HETERODOXIA J. Agardh 1898: 127

Phylum Rhodophyta – Family Delesseriaceae

Thallus complanately and marginally branched with flat branches alternately positioned, margins with irregular dentations, with a well developed midrib connected throughout the thallus; holdfast fibrous. Structure. Apical cells segmenting to give an axial filament and lateral and transverse pericentral cells, the lateral ones forming second-order cell rows with some cells cutting off adaxial and abaxial cells which form a broad blade of irregularly arranged primary cells; margin with short, simple or branched, outgrowths forming the dentations. Young blades monostromatic between the veins. Cortication of the midrib by anticlinal filaments of small cells and of the blade by 1 (–3) layers of cells, inner cortical cells dimidiate, outer cells then equivalent.

Reproduction: Gametophytes dioecious. Procarps scattered on the blades or on small leaflets from the midribs, with a 4-celled carpogonial branch and sterile groups; carposporophytes with a basal fusion cell and branched gonimoblast filaments with terminal chains of carposporangia. Cystocarps sunken in the blade, ostiolate, with a thick pericarp of anticlinal filaments of cells. Spermatangial sori on the blade surface, with the cortical cells cutting off initials with outer spermatangia.

Tetrasporangial sori scattered, with tetrasporangia cut off from inner cortical cells on both sides of the blade, with short anticlinal rows of outer cortical cells.

Type (and only) species: H. denticulata (Kuntze) J. Agardh 1898: 131.

Taxonomic notes: Silva et al. (1996, p. 456) discuss the authorship of the type species, treating Membranoptera delicatula Kuntze as a new name.


AGARDH, J.G. (1898). Species Genera et Ordines Algarum. Vol. 3, Part 3 - De dispositione Delesseriearum. (Gleerup: Lund.)

SILVA, P.C., BASSON, P.W. & MOE, R.L. (1996). Catalogue of the Benthic Marine Algae of the Indian Ocean. (Univ. California Press: Berkeley.)

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

Author: H. B. S. Womersley

Publication: Womersley, H.B.S. (24 February, 2003)
The Marine Benthic Flora of Southern Australia
Rhodophyta. Part IIID. Ceramiales – Delesseriaceae, Sarcomeniaceae, Rhodomelaceae
Reproduced with permission from The Marine Benthic Flora of Southern Australia Part IIID 2003, by H.B.S. Womersley. Australian Biological Resources Study, Canberra. Copyright Commonwealth of Australia.

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