Electronic Flora of South Australia Species Fact Sheet
Phylum Rhodophyta – Class Florideophyceae – Order Gigartinales – Family Hypneaceae
Selected citations: Harvey 1859b: 315. Hooker & Harvey 1847: 406. Kützing 1868: 8, pl. 22a, b. Silva, Meñez & Moe 1987: 49. Sonder 1848: 189; 1853: 685. Tanaka 1941: 243, fig. 16?
H. seticulosa J. Agardh 1852: 446; 1876: 562. Harvey 1855a: 552; 1863, synop.: xxxvi.
H. divaricata (Turner) Greville 1830: lix sensu Harvey 1855a: 552 (Alg. Aust. Exsicc. 338B); 1863, synop.: xxxvi. Sonder 1848: 190.
Fucus divaricatus Turner 1811: 110, p1. 181?
Thallus (Fig. 155C) light to medium red to red-brown, (5–) 10–20 cm high, tufted and much branched irregularly, with an entangled base and erect branches, usually not strongly percurrent; branches terete throughout, covered (usually densely) with slender spinous branchlets 1–3 mm long and 100–250 µm in diameter, mostly directed at right angles to the parent branch. Attachment by small, discoid, haptera; epiphytic, usually on Amphibolis, occasionally on other algae. Structure uniaxial, apical cell conspicuous, axial filament recognisable throughout, 20–50 (–90) µm in diameter with cells L/D 4–8, surrounded by a medulla 2–3 cells broad, cells ovoid and (30–) 50–90 (–150) µm in diameter with few secondary pit-connections, and a small-celled cortex 1–2 cells broad, outer cells ovoid and 10–20 µm in diameter, with odd smaller, often darker staining, cells 4–9 µm across cut off outwardly and lying over the margins of their initials. Rhodoplasts discoid, numerous per cell.
Reproduction: Sexual thalli dioecious. Carpogonial branches and early post-fertilization stages not observed. Carposporophyte (Fig. 155D) with a lax reticulum of elongate cells developed from several basal cells and with the upper cells in pit-connection with inner pericarp cells, producing clusters of smaller cells laterally (Fig. 155E) with each cell producing single (occasionally a chain of two) subspherical to ovoid carposporangia 25–35 µm in diameter. Cystocarps sessile on lateral branchlets, globular and 0.5–1.5 mm in diameter, base broad to slightly constricted, with a pericarp 3–5 cells thick, cells ovoid and separated, non-ostiolate. Spermatangia in sori (Fig. 155F) near base of branchlets, cut off from outer cortical cells via initials, in short, often branched chains (Fig. 154D), ovoid, 2–3 µm in diameter.
Tetrasporangia (Fig. 154E) in nemathecia near the base of the branchlets, basally to laterally pit-connected to inner cortical cells, ovoid, 50–80 µm long and 20–35 µm in diameter, zonately divided by successive but rapid divisions.
Type from "Nov. Holl."; apparently lost (see below).
Selected specimens: Port Denison, W. Aust., drift (Kraft, 14.xii.1971; AD, A41719). Swan R., W. Aust. (Clifton; AD, A18180). Safety Bay, W. Aust., drift (Womersley, 23.viii.1947; AD, A5821). King George Sound, W. Aust. (Harvey, Alg. Aust. Exsicc. 338B, as H. divaricata; AD, A18408). Esperance, W. Aust., drift (Firman, Dec. 1951; AD, A18897). Stun Bay, S. Aust. (AD, A679). Tiparra reef, S. Aust., 11 m deep on Amphibolis antarctica (Shepherd, 29.i.1972; AD, A41858). Tapley Shoal, S. Aust., 13 m deep on E side (Shepherd, 5.ii.1969; AD, A33756). Off West Beach, S. Aust., 6 m deep (Shepherd, 20.xi.1970; AD, A37687). Rocky Point, Kangaroo I., S. Aust., drift (Womersley, 26.viii.1950; AD, A13314). Muston, American R. inlet, Kangaroo I., S. Aust., upper sublittoral (Womersley, 27.viii.1950; AD, A15371). Cape Jaffa, S. Aust., drift, on Amphibolis (Womersley, 3.xii.1989; AD, A60042 -"Marine Algae of southern Australia" No. 341, and 10.xii.1991; AD, A61582). Low Head, Tas. (Perrin & Lucas, Jan 1931; AD, A47170).
Distribution: Port Denison, W. Aust., to Cape Jaffa, S. Aust., and N Tasmania.
Taxonomic notes: H. charoides appears to be essentially a western species extending largely along southern Australia, found under moderate wave action and commonly epiphytic on Amphibolis. Var. B delicatula Sonder (1848, p. 190), type in MEL, 501408, appears to be a separate species, probably not a Hypnea.
Silva et al. (1987, p. 48) claimed that the name of Lamouroux (1813) was invalid since Lamouroux did not provide a description. However, Art 44.2 recognises illustrations as validating a name, and H. charoides should be credited to Lamouroux. Lamouroux's figures are clearly of a Hypnea, but his original illustrated specimen is apparently not in CN; until it is found, Lamouroux's illustrations must serve to lectotypify the species. The type may have been collected by one of the early French expeditions, that of D'Entrecasteaux (1791–1794) or Baudin (1800–1804), and must have come from south-western or south-eastern coasts of Australia. A specimen from Tasmania, sent by Lamouroux to C. Agardh (1828, p. 141) was placed by C. Agardh as a synonym of Ceramium (Spyridia) filamentosa; this specimen must clearly be distinct from the type (illustrations).
It seems almost certain that Sonder's H. charoides is the same as Lamouroux's species, since there is only one species on southern Australian coasts with the features described above, and the divergent laterals of Lamouroux' illustration agree with this species, as does the Preiss specimen in MEL, 501408, named H. charoides by Sonder. H. seticulosa J. Agardh (1852, p. 446) was based.on H. charoides Sonder (1848, p. 189) since J. Agardh considered it distinct from H. charoides Lamouroux. The earlier name of F. divaricatus Turner is probably the same species but is made illegitimate by F. divaricatus Linnaeus (1753, p. 1159), a synonym of Fucus vesiculosus L.
H. charoides has cystocarps and carposporophytes typical of Hypnea, with groups of small cells cut off from cells of the reticulum producing mostly single, relatively large, carposporangia; occasionally however, two carposporangia may be in pit-connection, maturing together. The thallus surface, however, is more like that of Calliblepharis planicaulis, with a single layer of cortical cells cutting off occasional small cells which sometimes appear almost gland-like; this is less marked than in C. planicaulis, which has a carposporophyte with erect gonimoblast filaments producing chains of carposporangia. C. planicaulis also has compressed lower axes and branches and hamate branch ends, whereas H. charoides does not.
H. charoides has been recorded (e.g. by Silva et al. 1987, p. 49) from many countries apart from Australia. All such records need checking as to whether they agree with the above description.
AGARDH, C.A. (1828). Species Algarum. Vol. 2. (Mauritius: Greifswald.)
AGARDH, J.G. (1852). Species Genera et Ordines Algarum. Vol. 2, Part 2, pp. 337–720. (Gleerup: Lund.)
AGARDH, J.G. (1876). Species Genera et Ordines Algarum. Vol. 3, Part 1 - Epicrisis systematis Floridearum, pp. i-vii, 1–724. (Weigel: Leipzig.)
GREVILLE, R.K. (1830). Algae Britannicae. (Maclachlan & Stewart: Edinburgh.)
HARVEY, W.H. (1855a). Some account of the marine botany of the colony of Western Australia. Trans. R. Ir. Acad. 22, 525–566.
HARVEY, W.H. (1859b). Algae. In Hooker, J.D., The Botany of the Antarctic Voyage. Flora Tasmaniae. Vol. II, pp. 282–320.
HARVEY, W.H. (1863). Phycologia Australica. Vol. 5, Plates 241–300, synop., pp. i-lxxiii. (Reeve: London.)
HOOKER, J.D. & HARVEY, W.H. (1847). Algae Tasmanicae. Lond. J. Bot. 6, 397–417.
KÜTZING, F.T. (1868). Tabulae Phycologicae. Vol. 18. (Nordhausen.)
LAMOUROUX, J.V.F. (1813). Essai sur les genres de la famille des thalassiophytes non articulées. Ann. Mus. Hist. Nat., Paris 20, 21–47, 115–139, 267–293, Plates 7–13 (1–7).
LINNAEUS, C. (1753). Species Plantarum. Vol. 2. (Stockholm.)
SILVA, P., MENEZ, E.G. & MOE, R.L. (1987). Catalog of the benthic marine algae of the Philippines. Smithsonian Contr. Mar. Sci. No. 27.
SONDER, O.W. (1848). Algae. In Lehmann, C., Plantae Preissianae. Vol. 2, pp. 161–195. (Hamburg.)
SONDER, O.W. (1853). Plantae Muellerianae. Algae. Linnaea 25, 657–709.
TANAKA, T. (1941). The genus Hypnea from Japan. Sci. Pap. Inst. Algol. Res. Hokkaido Univ. 2, 227–250, Plates 53, 54.
TURNER, D. (1811). Fuci sive Plantarum Fucorum Generi a Botanicis Ascriptarum Icones Descriptiones et Historia. Vol. 3, pp. 1–148, Plates 135–196. (London.)
The Marine Benthic Flora of Southern Australia Part IIIA complete list of references.
Womersley, H.B.S. (14 January, 1994)
The Marine Benthic Flora of Southern Australia
Rhodophyta. Part IIIA, Bangiophyceae and Florideophyceae (to Gigartinales)
Reproduced with permission from The Marine Benthic Flora of Southern Australia Part IIIA 1994, by H.B.S. Womersley. Australian Biological Resources Study, Canberra. Copyright Commonwealth of Australia.
Illustrations in Womersley Part IIIA, 1994: FIGS 154D, E, 155 C–F.
Figure 154 enlarge
Fig. 154. A, B. Hypnea filiformis (A, AD, A19769; B, AD, A61512). A. Section of cortex with spermatangia. B. Transverse section of cortex with tetrasporangia. C. Hypnea ramentacea (AD, A42362). Section of cortex with spermatangia. D, E. Hypnea charoides (D, AD, A61582; E, AD, A60042). D. Section of cortex with spermatangia. E. Section of cortex with tetrasporangia. F. Hypnea valentiae (AD, A48965). Section of cortex with tetrasporangia. G–I. Catenella nipae (G, AD, A60381; H–I, AD, A26432). G. Habit of a tetrasporangial plant. H. Longitudinal section of apical segment with several carpogonial branches and a fusion cell producing gonimoblast initials. I. Longitudinal section of cortex with tetrasporangia. [H, I after Min-Thein & Womersley 1976.]
Figure 155 enlarge
Fig. 155. A, B. Hypnea ramentacea (AD, A43719). A. Branchlets with tetrasporangial nemathecia. B. Longitudinal section of branchlet with tetrasporangia. C–F. Hypnea charoides (D, E, AD, A61582; C, F, AD, A60042). C. Habit. D. Section of a cystocarp with clusters of carposporangia. E. Clusters of small cells of the carposporophyte and single, large, carposporangia. F. Spermatangial branchlets.
State Herbarium of South Australia