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Electronic Flora of South Australia Species Fact Sheet

Heterodoxia denticulata (Kuntze) J. Agardh 1898: 131.

Phylum Rhodophyta – Family Delesseriaceae

Selected citations: De Toni 1900: 697. Fuhrer et al. 1981, pl. 31. Huisman 1997: 201; 2000: 149. Huisman & Walker 1990: 429. Kylin 1924: 45, fig. 35b; 1956: 441. Lucas 1909: 36. May 1965: 401. Mazza 1926: No. 884. Shepherd & Womersley 1981: 366. Silva et al. 1996: 456. Wynne 1989a: 522, fig. 7F; 1996: 179.


Delesseria denticulata Harvey 1855a: 548, nom. illegit; 1863, pl. 244, synop.: xxxi. J. Agardh 1872: 59; 1876: 495. Reinbold 1897: 54. Sonder 1880: 24.

Membranoptera denticulata Kuntze 1891: 904.

Hydrolapatha denticulata (Kuntze) Kuntze 1898: 410.

Hypoglossum denticulatum J. Agardh sensu Lucas 1929b: 50; Lucas & Perrin 1947: 229, fig. 92.

Thallus (Fig. 28A) medium red to dark red-brown, (5–) 10–20 cm high, complanately and alternately marginally branched with well-developed midribs, branches 3–8 mm broad with delicate, slightly ruffled, wings with finely and irregularly dentate margins; wings lost below leaving a branched, subterete to compressed stipe 1–3 mm thick developed from the midrib. Holdfast fibrous, much branched, 5–15 mm across; epilithic. Structure. Growth by means of an obconical apical cell segmenting to give axial cells and within 1 or 2 segments lateral and transverse pericentral cells, the lateral pericentral cells forming second-order rows with the cells cutting off adaxial and abaxial cells or rows which develop rapidly to form a blade which overarches the apical cell (Fig. 28B); some marginal cells develop further to form the irregular, simple or branched, slender dentations. Cortication of the midrib (Fig. 28C) commences early, becoming many cells thick with anticlinal rows of small isodiametric cells 12–18 µm in diameter, overlying the central layer of larger cells 40–60 µm across; blades at first monostromatic but cortication also commencing early, becoming 3 cells thick generally and 5 cells thick near the midribs (primary cells angular, 20–35 µm across), with the inner cortical cells dimidiate, then outer layers equivalent, regularly arranged. Branching occurs by apical cells developing on the blade margins. Mature cells multinucleate; rhodoplasts discoid.

Reproduction: Gametophytes dioecious. Procarps scattered, often densely, over young blades or leaflets, usually opposite on both sides, with a 4-celled carpogonial branch and probably 2 sterile groups. Carposporophytes (Fig. 28E) with a basal, often 2-armed, fusion cell with branched gonimoblast filaments bearing chains of ovoid carposporangia 15–20 µm in diameter, maturing sequentially. Cystocarps (Fig. 28D) scattered, few to several per blade, sunken within the blade and convex to hemispherical above, 1.5–2.5 mm across, ostiolate; pericarp thick, of anticlinal rows 10–15 cells long. Spermatangial sod (Fig. 29A) on both sides of the midrib and the blade or on small leaflets, with several initials by division of the outer cortical cells, each producing 2–4 spermatangia (Fig. 29B).

Tetrasporangial sori (Fig. 29C) scattered on blades or on small leaflets arising from the midribs, 120–180 µm thick at sod, with tetrasporangia cut off from inner cortical cells on both sides of the blade (Fig. 29D), with outer cortical cells in anticlinal rows of 2–5 cells; tetrasporangia subspherical, 45–65 µm in diameter.

Type from Rottnest I., W. Aust. (Harvey); holotype (Trav. Set 235) in Herb. Harvey, TCD.

Selected specimens: 7 mile Beach, Dongara, W. Aust., drift (Kraft, 9.viii.1979; MELU, K7090a). North Beach, Perth, W. Aust., drift (Norris 1733, 27.iii.1959; AD, A22261). Point Peron, W. Aust., drift (Parsons 15.xi.1968; AD, A34295). Mangles Bay, Point Peron, W. Aust., 2.5–3.5 m deep (Kraft & Borowitzka, 11.xii.1984; MELU). Eyre, W. Aust., drift (Gordon, 22.xi.1968; AD, A34252). Twin Rocks, Head of Great Australian Bight, S. Aust., 20–22 m deep (Branden, 19.i.1991; AD, A61143). Elliston, S. Aust., 10–12 m deep in bay (Shepherd, 24.x.1969; AD, A34945). 6 km N of Pondalowie Bay, S. Aust., drift (Womersley, 13.iv.1963; AD, A26339).). Port Elliot, S. Aust., drift (Hussey, May 1898; AD, A36059) and (Baldock, 4.v.1963; AD, A30968). Pennington Bay, Kangaroo I., S. Aust., drift (Womersley, 11.ii.1956; AD, A20124). Cape Jaffa, S. Aust., drift (Womersley, 25.iv.2000; AD, A68502). Robe, S. Aust., drift (Womersley, 2.iv.1999; AD, A68096). Nora Creina, S. Aust., 1 m deep in crevice (Cenko, 19.iv.1989; AD, A59567).

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

Distribution: Houtman Abrolhos, W. Aust. to Nora Creina, S. Australia.

Taxonomic notes: The vein system of Heterodoxia is laterally rather than dichotomously branched, the tetrasporangial sod occur on the main branches as well as on small leaflets, and the older blade becomes tri-polystromatic (c.f. Wynne 1996, p. 176).


AGARDH, J.G. (1872). Bidrag till Florideernes Systematik. Acta Univ. Lund 8, 1–60.

AGARDH, J.G. (1876). Species Genera et Ordines Algarum. Vol. 3, Part 1 - Epicrisis systematis Floridearum, pp. i-vii, 1–724. (Weigel: Leipzig.)

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

DE TONI, G.B. (1900). Sylloge Algarum omnium hucusque Cognitarum. Vol. 4. Florideae. Sect. 2. pp. 387–776. (Padua.)

FUHRER, B., CHRISTIANSON, I.G., CLAYTON, M.N. & ALLENDER, B.M. (1981). Seaweeds of Australia. (Reed: Sydney.)

HARVEY, W.H. (1855a). Some account of the marine botany of the colony of Western Australia. Trans. R. Jr. Acad. 22, 525–566.

HUISMAN, J.M. & WALKER, D.I. (1990). A catalogue of the marine plants of Rottnest Island, Western Australia, with notes on their distribution and biogeography. Kingia 1, 349–459.

HUISMAN, J.M. (1997). Marine Benthic Algae of the Houtman Abrolhos Islands, Western Australia. In Wells, F.E. (Ed.) The Marine Flora and Fauna of the Houtman Abrolhos Islands, Western Australia, pp. 177–237. (W. Aust. Museum: Perth.)

HUISMAN, J.M. (2000). Marine Plants of Australia. (Univ. W. Aust. Press, Nedlands, W. Aust. & ABRS, Canberra, A.C.T.)

KUNTZE, O. (1891). Revisio generum Plantarum. Part II. 4. Algae, pp. 877–930. (Leipzig.)

KUNTZE, O. (1898). Revisio generum Plantarum. Part III. 2. Algae, pp. 385–437. (Leipzig.)

KYLIN, H. (1924). Studien über die Delesseriaceen. Lunds Univ. Årsskr. N.F. Avd. 2, 20(6), 1–111.

KYLIN, H. (1956). Die Gattungen der Rhodophyceen. (Gleerups: Lund.)

LUCAS, A.H.S. (1909). Revised list of the Fucoideae and Florideae of Australia. Proc. Linn. Soc. N.S.W. 34, 9–60.

LUCAS, A.H.S. (1929b). A census of the marine algae of South Australia. Trans. R. Soc. S. Aust. 53, 45–53.

MAY, V. (1965). A census and key to the species of Rhodophyceae (red algae) recorded from Australia. Contr. N.S. W. Natl Herb. 3, 349–429.

MAZZA, A. (1926). Saggio di Algologia Oceanica. Nuova Notarisia Nos. 779–810 & 811–925 privately printed.

REINBOLD, T. (1897). Die Algen der Lacepede und Guichen Bay und deren náherer Umgebung (Slid Australien), gesammelt von Dr. A. Engelhart-Kingston. Nuova Notarisia 8, 41–62.

SHEPHERD, S.A. & WOMERSLEY, H.B.S. (1981). The algal and seagrass ecology of Waterloo Bay, South Australia. Aquat. Bot. 11, 305–371.

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

SONDER, O.W. (1880). In Mueller, F., Fragmenta Phytographiae Australiae. Supplementum ad volumen undecinum: Algae Australianae hactenus cognitae, pp. 1–42, 105–107. (Melbourne.)

WYNNE, M.J. (1989a). A reassessment of the Hypoglossum group (Delesseriaceae, Rhodophyta), with a critique of its genera. Helgol. Meeresunters. 42, 511–534.

WYNNE, M.J. (1996). A revised key to genera of the red algal family Delesseriaceae. Nova Hedwigia 112, 171–190.

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.

Illustrations in Womersley Part IIIA, 2003: FIGS 28, 29 A–D.

Figure 28 image

Figure 28   enlarge

Fig. 28. Heterodoxia denticulata (A, D, E, AD, A59567; B, AD, A34945; C, AD, A34295). A. Habit. B. Blade apex with midrib and marginal spines. C. Transverse section of midrib and blade. D. Blade with cystocarps. E. Transverse section of cystocarp, showing fusion cell and chains of carposporangia.

Figure 29 image

Figure 29   enlarge

Fig. 29. A–D. Heterodoxia denticulata (A, B, AD, A61143; C, D, AD, A68096). A. Spermatangial sori on either side of midrib. B. Transverse section of a spermatangial sorus. C. Bladelet with a tetrasporangial sorus. D. Transverse section of a spermatangial sorus. E–G. Phycodrys australasica (E, F, AD, A37900; G, AD, A34369). E. Habit. F. Apex of blade showing segmentation. G. Transverse section of blade with midrib.

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