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Electronic Flora of South Australia Genus Fact Sheet
Phylum Rhodophyta – Family Delesseriaceae
Thallus foliose to divided and lacerate, monostromatic in young parts and often throughout but becoming tri- to polystromatic near the base and in the macroscopic veins. Macroscopic veins prominent, mostly subdichotomous, with or without lesser lateral veins; microscopic veins absent. Structure. Growth diffuse, marginal and intercalary, without conspicuous apical cells; mature cells multinucleate, nuclei lying in a plate across the cell centre in young cells, dispersed in mature cells; rhodoplasts single per cell, parietal to ribbon like, or several and discoid.
Reproduction: Gametophytes dioecious. Procarps scattered on either side of blades, with the supporting cell bearing a large-celled lateral sterile group, a 4-celled carpogonial branch and a small-celled basal sterile group. Carposporophyte first developing unilaterally, later radiating, with an extensive basal fusion cell and simple or branched chains of carposporangia. Cystocarps protuberant, ostiolate but often off-centre; pericarp thick, usually of anticlinal rows of 4–6 cells. Spermatangial sori ovate or aggregated, on young parts of blades, with spermatangia cut off from cortical cell initials.
Tetrasporangial sori with 2 layers of tetrasporangia cut off mainly from inner cortical cells and surrounded by cortical filaments.
Type species: S. laciniata Kylin 1924: 67 [= S. condensata (Reinsch) Ricker 1987, p. 283], from the Strait of Magellan, Chile.
Taxonomic notes: A genus of about 10 species, mainly subantarctic in distribution. Hommersand & Fredericq (1997b) have described the tribe Schizoserideae to include Schizoseris, Neuroglossum Kützing, Abroteia J. Agardh and Polycoryne Skottsberg, of which only the former occurs in southern Australia, with the recently described S. tasmanica and 2 other species (S. hymenena and S. perriniae) here transferred to Schizoseris from Nitophyllum. These, together with a fourth species, S. bombayensis, need further detailed study on their morphology, reproduction and seasonal development. Their main area of distribution appears to be in SE Tasmania, where a further possible species (S of Huon I., 25 m deep, Edgar, 3.vii.2000; AD, A68829) occurs.
Schizoseris is characterised vegetatively by the relatively large (except S. bombayensis), foliose to lacerate thalli, monostromatic in young parts, with (usually) conspicuous dichotomous macroscopic veins but no microscopic veins.
References:
HOMMERSAND, M.H. & FREDERICQ, S. (1997b). Characterization of Schizoseris condensata, Schizoserideae trib. nov. (Delesseriaceae, Rhodophyta). J. Phycol. 33, 475–490.
KYLIN, H. (1924). Studien über die Delesseriaceen. Lunds Univ. Årsskr. N.F. Avd. 2, 20(6), 1–111.
RICKER, R.W. (1987). Taxonomy and biogeography of Macquarie Island Seaweeds. (British Museum (N.H.): London.)
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 SCHIZOSERIS
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1. Thallus | S. bombayensis |
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1. Thallus usually | 2 |
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2. Dichotomous veins very faint, present only in lower thallus | S. tasmanica |
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2. Dichotomous veins prominent, extending throughout the thallus | 3 |
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3. Base of thallus not stipe-like, short, veins subdichotomous from the base | S. hymenena |
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3. Base of thallus with branched stipes | S. perriniae |
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Email Contact: State Herbarium of South Australia |
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