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Kew Bulletin

, Volume 64, Issue 1, pp 123–128 | Cite as

Isoetes eludens (Isoetaceae), a new endemic species from the Kamiesberg, Northern Cape, South Africa

  • J. P. Roux
  • S. D. Hopper
  • R. J. Smith
Article

Summary

Isoetes eludens, a new, highly localised, endemic species from the Kamiesberg, Northern Cape is described. The aquatic species grows in a shallow temporary gnamma or !gau (rock pool) in Kamiesberg gneiss at an altitude of 1,284 m. It is characterised by a short, strongly 3-lobed stem, relatively short, and broad estomate sporophylls, a complete velum, the presence of an outer sporangium sack (a feature not previously reported for the genus), graphite-black, laevigate megaspores with a narrow, but tall laesura, microspores with near smooth proximal surfaces but with a papillate distal surface, the absence of a ligule and labium, and simple roots with few root-hairs. The systematic relationship of the species is difficult to determine as a result of convergent evolution in the genus. The sporangium sack does not support an affinity with any of the known species. Further surveys are needed to establish the geographical extent and conservation status of this remarkable local endemic.

Key Words

Isoetaceae Isoetes eludens Kamiesberg Northern Cape South Africa 

Notes

Acknowledgements

The first author wishes to express his thanks to SDH for bringing this unusual species to his attention. Also to Dr J. P. Rourke who accompanied us, on different occasions to the locality. Dr J. Manning, Dr D. Snijman and Dr C. Paterson-Jones have also participated in exploratory field work in the Kamiesberg. Appreciation also goes to the Department of Tourism, Environment and Conservation, Northern Cape for providing the necessary permits to collect the material in the province, and to Mr J. J. P. Beukes, owner of the farm Damsland for giving permission to study and collect the plants on his land. Michelle Smith prepared the electronic versions of the illustrations and distribution map, and Katherine Challis provided the Latin diagnosis.

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Copyright information

© The Board of Trustees of the Royal Botanic Gardens, Kew 2009

Authors and Affiliations

  1. 1.South African National Biodiversity InstituteCompton HerbariumClaremontSouth Africa
  2. 2.Royal Botanic Gardens, KewRichmondUK
  3. 3.School of Plant BiologyUniversity of Western AustraliaCrawleyAustralia

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