Notes on Vallisneria (Hydrocharitaceae) in Australia, with descriptions of two new species

Abstract

descriptions of two new species. Telopea 7(2): 111-118. Five species of Vallisneria are recognised from Australia, namely the cauline-leafed species V. caulescens and V. triptera and the non-cauline or tufted species V. americana (var. americana), V. nana and V. annua. Two of these, Vallisneria triptera and Vallisneria annua, are described here as new species from northern Australia, and an earlier name, Vallisneria nana R. Br., reinstated for a common Australian species. V. gracilis Bailey is recognised as a taxonomic synonym of V. nana, although many of the specimens previously identified as V. gracilis are now included in V. annua. Notes on all species and a key are given. The problems of comparing taxa growing in different countries and of applying correct names are discussed.

Surrey W. L. Jacobs (1946-2009) and aquatic plant research in Australia

“…Originally I planned to work with Surrey on Zostera during my sabbatical visit to Australia in 1999-2000, but he had other thoughts. His interest in Vallisneria was first whetted by the discovery of two new species (Jacobs & Frank 1997). Soon afterwards he wrote a popular account of the Australian Vallisneria species for the aquarist journal Aqua-Planta (Jacobs 1999a(Jacobs , 1999b, which reinforced his 'outreach' commitment to disseminate the practical applications of his taxonomic research.…”

“…His interest in Vallisneria was first whetted by the discovery of two new species (Jacobs & Frank 1997). Soon afterwards he wrote a popular account of the Australian Vallisneria species for the aquarist journal Aqua-Planta (Jacobs 1999a(Jacobs , 1999b, which reinforced his 'outreach' commitment to disseminate the practical applications of his taxonomic research. So, soon after Surrey first picked me up to begin our Zostera field work, he stopped to point out a stand of Vallisneria, indicating that the Australian botanists had been calling it V. americana.…”

“…Previous treatments had recognised only two or three species in the country, and had virtually ignored the caulescent taxa (most species are rosulate). Surrey's field work had uncovered V. triptera (Jacobs & Frank 1997), a caulescent species so conspicuous that it is hard to believe it could have gone unnoticed for so long. This and the previously named caulescent V. caulescens were quite distinct from the caulescent Maidenia, an Australian endemic believed to represent the closest relative of the genus, but arguably belonging to it (Aston 1973).…”

“…Aston (1973) also recognised a second rosulate species, V. gracilis, which had been distinguished by its very fine foliage. Jacobs and Frank (1997) began to sort out these taxa, ultimately deciding that the more tropical segregate of V. spiralis s. lat. should be recognised as distinct (as V. nana) from the temperate segregate, which they called V. americana in deference to the latest global taxonomic revision by Lowden (1982).…”

Carbon and nitrogen partitioning in the freshwater submerged macrophyte Vallisneria gigantea in response to ultraviolet-B irradiance

“…Investigators have demonstrated that aquatic macrophytes play a major role in nutrient cycling of many freshwater systems (Ozimek et al 1990;Wigand et al 1997;Morris et al 2003;Huss and Wehr 2004). The genus Vallisneria includes approximately ten species, with Vallisneria gigantea Graebner found in Australia, New Zealand, Malaysia and some parts of the USA (Jacobs and Frank 1997). This species is known to be sensitive to irradiation and inorganic carbon conditions (Korschgen et al 1997;Wigand et al 1997).…”