Electronic Flora of South Australia Genus Fact Sheet

Genus POLLEXFENIA Harvey 1844b: 431

Phylum Rhodophyta – Family Rhodomelaceae – Tribe Pterosiphonieae

Thallus erect, membranous, complanately branched, usually with lobed, flat, terminally rounded lateral branches, with fine, branching veins within the laterals. Holdfast discoid or clasping on the host (usually Amphibolis) or epilithic. Structure. Branch apices with numerous apical cells producing congenitally fused systems, the axial cells cutting off 4 pericentral cells, 2 on each surface, and branching usually every two cells, with unicellular (becoming multicellular) primordia cut off alternately on each side between the axial branches. Pericentral cells dividing transversely on both dorsal and ventral sides so that on maturity 2–8 cells correspond to each axial cell in length. Thallus mostly 2 cells thick, with or without a defined midrib. Trichoblasts in tufts on the thallus surface above the axial cells, arising mainly from the primordia, or on the margins.

Reproduction: Reproductive structures associated with the surface or marginal trichoblast tufts.

Type species: P. pedicellata Harvey 1844b: 431.

Taxonomic notes: Gametophytes dioecious. Procarps with a 4-celled carpogonial branch; carposporophytes with a basal fusion cell, branched gonimoblast and clavate terminal carposporangia; cystocarps ovoid, pericarp ecorticate. Spermatangial organs on branches of trichoblasts.

Stichidia in tufts on thallus surface or margin, with tetrasporangia in a close spiral, single per segment, with 2–3 cover cells.

A genus of 3 or 4 species, confined to southern Australia, characterised especially by habit, 4 pericentral cells, and transverse division of the pericentral cells. Apical development is similar on both sides, i.e. not dorsiventral or heteromorphic.

There has been considerable confusion concerning the names Pollexfenia Harvey (1844b, p. 431) and Papenfussia, which Kylin (1938, p. 15) used for the South Africa plant (Delesseriaceae) on the basis that Pollexfenia was a southern Australian genus of the Rhodomelaceae.

Harvey (1844b, p. 431), in describing Pollexfenia in his "Algae of Tasmania", described P. pedicellata first, following which he characterised the South African P. laciniata. He also (and in 1846, p. 382) stated that the genus was "founded on a plant from the Cape of Good Hope". In view of this comment, Papenfuss (1942, p. 446) considered P. laciniata should be the type species, quoting Harvey's comment, but omitting Harvey's (1847, p. 22) later comment referring to P. pedicellata, viz. "The first, to which the name Pollexfenia will be preserved, is distinguished by its delicate substance being traversed internally by a system of pellucid, branching striae, and by having stichidia". Kylin (1956, p. 444) considered Pollexfenia should be retained for the Australian genus and Papenfussia for the South African plant (with the older name laciniata replacing his elegans). Neither Papenfuss nor Kylin commented on Harvey's protologue for Pollexfenia, which agrees very largely with pedicellata and not with laciniata. Since the ICBN (Art. 9.13(b), 10.5) states clearly that the type must not be in conflict with the protologue, it is clear that P. pedicellata from southern Australia must be the type species of Pollexfenia, and the South African taxon is correctly known as Papenfussia laciniata. Papenfussia includes 2 South African species (Stegenga et al. 1997, p. 493) and probably also "Pollexfenia" japonica Yoshida & Mikami (1990, p. 200, figs 1–26; Yoshida 1998: 992) from Japan.

Pollexfenia Harvey (1844b, p. 431) now includes and replaces Jeannerettia Hooker & Harvey in Harvey (1847, p. 20).

References:

HARVEY, W.H. (1844b). Algae of Tasmania. Lond. J. Bot. 3, 428–454.

HARVEY, W.H. (1847). Nereis Australis, pp. 1–69, Plates 1–25. (Reeve: London.)

KYLIN, H. (1938). Verzeichnis einiger Rhodophyceen von Stidafrika. Lunds Univ. Årsskr. N.F. Avd. 2, 34 (8), 1–26, Plates 1–8.

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

PAPENFUSS, G.F. (1942). Notes on algal nomenclature: I. Pollexfenia, Jeannerettia and Mesotrema. Proc. Nat. Acad. Sci. 28, 446–451.

STEGENGA, H., BOLTON, J.J. & ANDERSON, R.J. (1997). Seaweeds of the South African West Coast. Contributions from the Bolus Herbarium, No. 18.

YOSHIDA, T. & MIKAMI, H. (1990). Pollexfenia japonica sp. nov. (Delesseriaceae, Rhodophyta) from Central Honshu, Japan. Phycologia 29, 200–205.

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

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.

KEY TO SPECIES OF POLLEXFENIA

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