Electronic Flora of South Australia Genus Fact Sheet

Genus PNEOPHYLLUM Kützing 1843: 385

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

Thallus encrusting, epiphytic and affixed by cell adhesion. Structure pseudoparenchymatous; organisation dorsiventral; construction dimerous, consisting of a single ventral layer of branched filaments composed of non-palisade cells, and unicellular or multicellular simple or branched filaments that arise more or less perpendicularly from cells of ventral layer filaments; cells of adjacent filaments joined by cell-fusions, secondary pit-connections absent; epithallial cells terminating filaments at the thallus surface, distal walls rounded or flattened but not flared; trichocytes present or absent, if present usually occurring singly at the thallus surface, not becoming buried within the thallus.

Reproduction: Vegetative reproduction unknown. Gametangia, carposporangia, tetrasporangia and bisporangia borne in uniporate conceptacles; gametangia and carposporangia usually formed on separate plants from tetrasporangia and bisporangia.

Gametangial plants monoecious; carpogonia and spermatangia produced in separate conceptacles or rarely in the same conceptacle. Carpogonia terminating 3-celled filaments arising from the female conceptacle chamber floor. Carposporophytes developing within older female conceptacles after karyogamy, when mature composed of a large central fusion cell and short gonimoblast filaments bearing terminal carposporangia, conceptacle pores surrounded by or lacking coronas of filaments and flush with or sunken below the surrounding thallus surface. Spermatangial filaments unbranched, borne on the floor of male conceptacle chambers.

Tetrasporangia and bisporangia formed across the chamber floor or peripheral to a central columella, conceptacle roofs formed by filaments either surrounding sporangial initials or surrounding and interspersed amongst sporangial initials, pores surrounded by or lacking coronas of filaments and flush with or sunken below the surrounding thallus surface; each mature sporangium lacking an apical plug, zonately divided.

Type species: Pneophyllum fragile Kützing 1843: 385

Taxonomic notes: The genus was established by Kützing (1843) for a single species, P. fragile, but generally was not recognised until Chamberlain (1983) provided an account of the type specimen and the species in the British Isles. Pneophyllum has been distinguished from Spongites by the mode of tetrasporangial conceptacle roof development (Penrose & Woelkerling 1992b). Recent data (Penrose, unpubl.) have shown that this character may be unreliable in distinguishing the two genera, and further studies are needed to evaluate this.

References:

CHAMBERLAIN, Y.M. (1983). Studies in the Corallinaceae with special reference to Fosliella and Pneophyllum in the British Isles. Bull. Br. Mus. Nat. Hist. (Bot.) 11, 291–463.

KÜTZING, F.T. (1843). Phycologia generalis. (Leipzig.)

PENROSE, D. & WOELKERLING, Wm.J. (1992b). A reassessment of Pneophyllum (Corallinaceae, Rhodophyta) and its relationships to Spongites. Phycologia 30, 495–506.

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

Author: W.J. Woelkerling (with some genera by D.L. Penrose)

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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