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Electronic Flora of South Australia Species Fact Sheet

Hymenocladia usnea (R. Brown ex Turner)J. Agardh 1852: 772; 1871: 454; 1876: 313.

Phylum Rhodophyta – Class Florideophyceae – Order Rhodymeniales – Family Rhodymeniaceae

Selected citations: De Toni 1900b: 502. De Toni & Fora 1923: 29. Harvey 1859a: pl. 118; 1859b: 318. Kylin 1931: 24; 1956: 338, fig. 266C. Lucas 1929b: 49. Lucas & Perrin 1947: 197, fig. 63. May 1965: 388. Reinbold 1897: 52; 1899: 45. Sonder 1853: 695; 1881: 17. Sparling 1957: 365, fig. 14a-d. Tisdall 1898: 506. Wilson 1892: 179. Womersley 1950: 176.


Fucus usneus R. Brown ex Turner 1819: 70, pl. 225.

Chondria usnea (R. Brown ex Turner)C. Agardh 1822: 359.

Halymenia usnea (R. Brown ex Turner)Greville 1830, synop.: lxii. Kützing 1849: 717; 1867: 1, pl. 1d, e.

Gracilaria ramalina Harvey 1863: pl. 260.

Hymenocladia ?ramalina Harvey 1855a: 553. J. Agardh 1871: 454; 1876: 313. De Toni 1900b: 502.Kylin 1931: 24, pl. 12 fig. 28. May 1965: 387. Sonder 1881: 17. Sparling 1957: 365. Tisdall 1898: 506.

Chondrococcus squarrosus Kützing 1867: 28, pl. 96a, b. De Toni 1905: 1677.

Hymenocladia gracilarioides J. Agardh 1876: 313. De Toni 1900b: 500. Kylin 1931: 24, pl. 12 fig. 27. May 1965: 387. Sonder 1881: 17. Sparling 1957: 367. Tisdall 1898: 506. Wilson 1892: 179.

Chrysymenia husseyana J. Agardh 1894: 130. FIG. 43 ,

Thallus (Fig. 43A) erect, medium red to dark red-brown, 10–30 cm high, complanately and pinnately to tri-pinnately branched, branch axes 2–8 mm broad and usually broadest centrally, bearing closely set, compressed, marginal laterals 1–3 mm broad, the ultimate ramuli compressed, 2–10 (–20) mm long and 1–2 mm broad, simple or furcate. Holdfast discoid, around the host stems and 1–3 mm across, bearing one to several fronds; epiphytic on Amphibolis and possibly epilithic. Structure multiaxial, developing a cortex (Fig. 43C, E) 2–3 (–4) cells thick, outer cells ovoid to elongate and 2–3 µm in diameter, grading over 1–2 cells to the medulla 2–4 cells across, larger inner cells ovoid (in branch transverse section) and 100–150 µm in diameter with walls 4–10 µm thick, with interspersed smaller ovoid cells 20–40 µm in diameter; secondary pit-connections frequent. Rhodoplasts ovoid to elongate, in chains in inner cells.

Reproduction: Gametangial thalli dioecious (or monoecious?). Carpogonial branches 4-celled, borne with a 2-celled auxiliary cell branch on inner cortical cells. Carposporophytes (Fig. 43B) with a basal, branched, fusion cell complex with the upper cells all forming carposporangia, with secondary lobes developed later; carposporangia ovoid to angular, 40–90 µm across. Basal nutritive tissue well developed with vertical chains of cells (Fig. 43B), erect filaments disintegrating early. Cystocarps scattered, hemispherical to conical, 1–1.5 mm in diameter; pericarp 160–200 µm and 8–16 cells thick, cells ovoid (innermost cells slightly stellate), with a prominent ostiole. Spermatangia in discrete surface sori 200–800 µm across (Fig. 43C), with ovoid spermatangia 2–3 µm in diameter cut off from elongate initials on outer cortical cells (Fig. 43D).

Tetrasporangia (Fig. 43E) scattered, transformed from intercalary inner cortical or outer medullary cells, subspherical to ovoid, 70–140 µm in diameter, tetrahedrally divided.

Type from the Kent Is, Bass Strait (R. Brown); holotype in BM.

Selected specimens: Port Denison, W. Aust., drift (Womersley, 31.viii.1947; AD, A5858). Israelite Bay, W. Aust., 7 m deep on Amphibolis (Kirkman, 18.xii.1981; AD, A56672). Smooth I., Isles of St Francis, S. Aust., 22 m deep on Amphibolis (Shepherd, 29.iii.1980; AD, A52253). Elliston, S. Aust., 7 m deep on Amphibolis (Shepherd, 25.x.1971; AD, A42589). Tiparra Reef, Spencer Gulf, S. Aust., 11 m deep on Amphibolis griffithii (Shepherd, 24.ii.1971; AD, A38233). Port Elliot, S. Aust., drift on Amphibolis (Womersley, 10.viii.1957; AD, A21134 and 28.v.1994; AD, A63564). Vivonne Bay, Kangaroo I., S. Aust., drift (Womersley, 17.i.1950; AD, Al2650). Cape Jaffa, S. Aust., drift (Womersley, 10.xii.1991; AD, A61579). Boatswains Point, Guichen Bay, S. Aust., drift (Womersley, 17.v.1965; AD, A29270). Dutton Bay, Portland, Vic., drift (Womersley, 13.iv.1959; AD, A22691). Point Lonsdale, Vic., drift (Sinkora A1130, 8–12.xi.1970; AD, A62607). Off Point Nepean, Port Phillip Hds, Vic., 5–7 m deep (Borowitzka & Walker, 3.xii.1983; AD, A55423). Walkerville, Vic., drift (Sinkora A1566, 23.ii.1972; AD, A43173).

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

Distribution: Port Denison, W. Aust., to Walkerville, Vic., and Kent Is, Bass Strait. May (1949, p. 296) records it from Tathra, N.S.W., but this record is referred to Callophyllis rangiferinus by Millar & Kraft (1993, p. 20).

Taxonomic notes: Hymenocladia usnea is variable in habit, especially in the degree of development of the distichous ramuli on the laterals, but these are always compressed and broader than those of H. divaricata.

The lectotype of H. ramalina Harvey, from King George Sound, W. Aust., is in Herb. Harvey, TCD. It is his Tray. Set No. 87 and is a loosely branched form of H. usnea.

The holotype of Chondrococcus squarrosus Kützing, from Phillip I., Vic. (Mueller), is in Herb. Kützing, L, 940, 284...251. It is an old and battered specimen of H. usnea, growing on an Amphibolis stem.

The lectotype (Kylin 1931, pl. 12 fig. 27) of H. gracilarioides J. Agardh, from "Nov. Holl. Occid. (Mueller)" is in Herb. Agardh, LD, 26253. It is a slender, regularly subdistichously branched plant of H. usnea.

The lectotype of Chrysymenia husseyana J. Agardh, from Encounter Bay, S. Aust. (Hussey), is in Herb. Agardh, LD, 26299. It is a moderately broad-branched specimen of H. usnea.


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

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SONDER, O.W. (1881). In Mueller, F., Fragmenta Phytographiae Australiae. Supplementum ad volumen undecinum: Algae Australianae hactenus cognitae, pp. 1–42, 105–107. (Melbourne.)

SPARLING, S.R. (1957). The structure and reproduction of some members of the Rhodymeniaceae. Univ. Calif Pubis Bot. 29, 319–396.

TISDALL, H.T. (1898). The algae of Victoria. Rep. 7th Meet. Aust. Ass. Adv. Sci., Sydney, 1898, pp. 493–516.

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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.

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