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Electronic Flora of South Australia Genus Fact Sheet

Genus LITHOPHYLLUM Philippi 1837: 387

Phylum Rhodophyta – Class Florideophyceae – Order Corallinales – Family Corallinaceae – Subfamily Lithophylloideae

Thallus encrusting to warty, lumpy, fruticose, layered or foliose, epigenous and partially to completely affixed by cell adhesion or envelopment of host axes or unattached and free-living as rhodoliths; genicula absent. Structure pseudoparenchymatous; organisation dorsiventral in crustose portions and lamellate branches but radial in protuberant branches; construction monomerous, dimerous or both; monomerous portions consisting of a single system of branched, laterally cohering, filaments that collectively contribute to a ventrally or centrally situated core and a peripheral region where portions of core filaments or their derivatives curve outwards towards the thallus surface; dimerous portions consisting of two distinct groups of laterally cohering filaments/cells: a unistratose ventral layer in which each filament is composed of palisade cells, non-palisade cells or both, and secondly epithallial cells or multicellular filaments arising dorsally and more or less perpendicularly from cells of ventral layer filaments; cell elongation characteristics uncertain; cells of adjacent filaments joined by secondary pit-connections, cell-fusions rare or absent; epithallial cells terminating most filaments at thallus surface, distal walls rounded or flattened but not flared; haustoria unknown; trichocytes uncommon, occurring singly.

Reproduction: Vegetative reproduction by thallus fragmentation. Gametangia, carposporangia, tetrasporangia and bisporangia borne in uniporate conceptacles; gametangia and carposporangia formed on separate thalli from tetrasporangia and bisporangia.

Gametangial thalli monoecious or dioecious; carpogonia and spermatangia produced in separate conceptacles or rarely in the same conceptacle. Carpogonia terminating 2- or 3-celled filaments arising from the female conceptacle chamber floor. Carposporophytes composed of a central fusion cell and short gonimoblast filaments bearing terminal carposporangia. Spermatangial filaments unbranched, confined to the male conceptacle chamber floor.

Tetrasporangia and bisporangia scattered across the conceptacle chamber floor or peripheral to a central columella; mode of roof formation uncertain in most species; each mature sporangium lacking an apical plug and containing zonately arranged tetraspores or two bispores.

Lectotype species: L. incrustans Philippi 1837: 388; designated by Foslie (1898a: 6).

Taxonomic notes: Over 650 species and infraspecific taxa have been ascribed to Lithophyllum (Woelkerling & Campbell 1992, p. 2); most are poorly known. The most recent detailed account of the type species is that of Chamberlain & Irvine (1994b, pp. 75–81, frontispiece, figs 6, 7C, 19C, 27–29, Tables 2, 3). Woelkerling (1983b, pp. 315–317, figs 15–23) provides an in depth account of the holotype collection of L. incrustans; Edyvean & Moss (1984) give data on conceptacle development, and the population biology and ecology of L. incrustans has been studied by Edyvean & Ford (1984a, 1984b, 1986a, 1986b, 1987) and Ford et al. (1983). Details relating to generic etymology, nomenclature, synonymy, infrageneric classification, etc. are provided by Woelkerling (1988, pp. 97–104, 111–113). This account of southern Australian species updates Woelkerling & Campbell (1992), who considered Titanoderma to be a heterotypic synonym of Lithophyllum (also see Campbell & Woelkerling 1990). Woelkerling (1991) has concluded that Perispermon is also a heterotypic synonym of Lithophyllum.

Notes on other taxa reported from southern Australia

Woelkerling & Campbell (1992, pp. 97–101) provide information on 12 additional species and infraspecific taxa that at some stage were ascribed to Lithophyllum and reported from southern Australia. These include taxa whose status is uncertain, incorrect records, and taxa now known to belong to other genera or conspecific with taxa belonging to other genera.

References:

CAMPBELL, S.J. & WOELKERLING, W.J. (1990). Are Titanoderma and Lithophyllum (Corallinaceae, Rhodophyta) distinct genera? Phycologia 29, 114–125.

CHAMBERLAIN, Y.M. & IRVINE, L.M. (1994b). Lithophylloideae Setchell. In Irvine, L. M. & Chamberlain, Y. M. (Eds), Seaweeds of the British Isles. Volume 1 Rhodophyta Part 2B Corallinales, Hildenbrandiales pp. 58–112. (HMSO: London.)

EDYVEAN, R.G.J. & FORD, H. (1984a). Population biology of the crustose red alga Lithophyllum incrustans Phil. 2. A comparison of populations from three areas of Britain. Biol. J. Linn. Soc., London 23, 353–363.

EDYVEAN, R.G.J. & FORD, H. (1984b). Population biology of the crustose red alga Lithophyllum incrustans Phil. 3. The effects of local environmental variables. Biol. J. Linn. Soc., London 23, 365–374.

EDYVEAN, R.G.J. & FORD, H. (1986a). Spore production by Lithophyllum incrustans (Corallinales, Rhodophyta) in the British Isles. Br. phycol. J. 21, 255–261.

EDYVEAN, R.G.J. & FORD, H. (1986b). Population structure of Lithophyllum incrustans (Philippi). (Corallinales, Rhodophyta) from south-west Wales. Field Stud. 6, 397–405.

EDYVEAN, R.G.J. & FORD, H. (1987). Growth rates of Lithophyllum incrustans (Corallinales, Rhodophyta) from south west Wales. Br. phycol. J. 22, 139–146.

EDYVEAN, R.G.J. & MOSS, B.L. (1984). Conceptacle development in Lithophyllum incrustans Philippi (Rhodophyta, Corallinaceae). Botanica Mar. 27, 391–400.

FORD, H., HARDY, F.G. & EDYVEAN, R.G.J. (1983). Population biology of the crustose red alga Lithophyllum incrustans Phil. Three populations on the east coast of Britain. Biol. J. Linn. Soc., London 19, 211–220.

FOSLIE, M. (1898a). Systematical survey of the lithothamnia. K. norske Vidensk. Selsk. Skr. 1898(2), 1–7.

PHILIPPI, R. (1837). Beweis dass die Nulliporen Pflanzen sind. Arh. Naturgesch. 3, 387–393, Plate 9 figs 2–6.

WOELKERLING, W.J. & CAMPBELL, S.J. (1992). An account of southern Australian species of Lithophyllum (Corallinaceae, Rhodophyta). Bull. Br. Mus. Nat. Hist., Bot. Ser. 22, 1–107.

WOELKERLING, W.J. (1983b). A taxonomic reassessment of Lithophyllum Philippi (Corallinaceae, Rhodophyta) based on studies of R.A. Philippi's original collections. Br. phycol. J. 18, 299–328.

WOELKERLING, Wm.J. (1988). The Coralline Red Algae. [British Museum (N.H.): London.]

WOELKERLING, W.J. (1991). The status and disposition of Perispermon (Corallinaceae, Rhodophyta). Phycologia 30, 135–144.

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

Author: W.J. Woelkerling

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.

KEY TO SPECIES OF LITHOPHYLLUM

1. Pore canals of mature tetrasporangial and bisporangial conceptacles completely occluded by enlarged cells (Figs 94E; 95D, E; 97E)

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1. Pore canals of mature tetrasporangial and bisporangial conceptacles lined with cells that may project somewhat into but do not completely occlude the entire canal (Figs 98C, 100F, 102E, 104E), although the canal sometimes appears blocked by mucilaginous material

4

2. Floors of tetrasporangial and bisporangial conceptacle chambers usually situated 8–20 cells below the surrounding thallus surface (Fig. 94E); conceptacle roofs usually more or less flush with the surrounding thallus surface; vegetative filaments arising from the single ventral layer of filaments in a dimerous thallus, commonly composed of 10 or more cells

L. johansenii

2. Floors of tetrasporangial and bisporangial conceptacle chambers usually situated 1--3 cell layers below the surrounding thallus surface (Figs 95E, 97E); conceptacle roofs commonly protruding above the surrounding thallus surface; vegetative filaments arising from the single ventral layer of filaments in a dimerous thallus rare and only 2 or 3 cells long, often replaced by epithallial cells only

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3. Pore canal occluded by a cluster of overlapping, more or less tubular and sometimes clasping or inflexed cells that are derived from at least the first two rows of roof filaments flanking the pore canal and that usually project beyond the surrounding roof surface (Fig. 95D, E)

L. chamberlainianum

3. Pore canal occluded by 2 or 4 angular cells that are derived only from the row of roof filaments immediately flanking the pore canal and that do not project beyond the surrounding roof surface (Fig. 97D, E)

L. irvineanum

4. Floors of tetrasporangial and bisporangial conceptacle chambers usually situated 1–3 (–5) cell layers below the surrounding thallus surface (Fig. 100F)

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4. Floors of tetrasporangial and bisporangial conceptacle chambers usually situated 6 or more cell layers below the surrounding thallus surface (Figs 102E, 104E)

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5. Thallus composed of a number of overlapping layers of flattened and horizontally expanded branches that give a terraced appearance in surface view (Fig 98B); dimerous development limited to epithallial cells in vegetative parts of thallus

L. prototypum

5. Thallus lacking overlapping layers of flattened and horizontally expanded branches or with sporadic branches that do not form numerous overlapping layers giving a terraced appearance in surface view; dimerous development commonly but not always involving multicellular filaments

L. pustulatum

6. Tetrasporangial and bisporangial conceptacle chambers (155–) 190–235 (–280) pm in diameter; conceptacle roofs commonly 2–4 cells thick above the chamber

L. corallinae

6. Tetrasporangial and bisporangial conceptacle chambers (255–) 320–410 (–445) pm in diameter; conceptacle roofs commonly 4–7 cells thick above the chamber

L. frondosum


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