A taxonomic revision of Stuckenia (Potamogetonaceae) in Asia, with notes on the diversity and variation of the genus on a worldwide scale

Abstract

A taxonomic revision of the Asian species of Stuckenia, a segregate of Potamogeton, is presented. Six species are recognized and their morphological descriptions, nomenclature and typification of relevant names are given. Distributions of all species are described and lists of representative specimens and distribution maps provided. Lectotypes are designated for 24 names and nomenclatural types are listed for 22 additional names. The correct name for the species known as Potamogeton recurvatus is Stuckenia pamirica (Baagöe) Z. Kaplan, comb. nova. Morphological variation at different levels within the genus is described and compared with different concepts of its taxonomic interpretation. Instructions on examination of key characters are given, together with a key to species. Colour photographs illustrate the general appearance of species as well as many identification details. The pattern of variation and taxonomic validity of the Siberian morphotypes S. subretusa and S. austrosibirica are analyzed. The plasticity of diagnostic characters of P. juncifolius and of P. helveticus from the European Alps, the infraspecific classification of S. filiformis in North America, and the taxonomic status of S. punensis described from Peru are also discussed. © Institute of Botany, Academy of Sciences of the Czech Republic 2008.