An account of the species ofPotamogeton L. (Potamogetonaceae)

Abstract

An account of the taxonomy of the genus Potamogeton L. with special reference to species description and delimitation is presented. A key to the species is given, based as far as possible on vegetative characters. Detailed descriptions are provided for a total of 69 species which are regarded as sufficiently well known. Special emphasis is laid both on a complete list of relevant characters as well as on the judgement of their respective diagnostic values. All important synonyms are listed allowing direct access to most of the relevant taxonomic and floristic Potamogeton literature. 50 confirmed hybrids are listed and assigned to their putative parent species. Questions with respect to the taxa listed are formulated in notes on each of the species. A more general view and questions on future Potamogeton research are summarized in the conclusions."It is to be regretted that we never arrive to the truth but through some mistake or another" (J. O. Hagstrrm 1916)

A dynamic evolution of chromosome in subgenus Potamogeton revealed by physical mapping of rDNA loci detection

“…The meaning of such comprehensive aneuploidy, which leads to inconspicuous effects, genetically and morphologically, is still unknown. It is noteworthy that the variability of chromosome number was more commonly evident in tetraploids rather than in diploids, associated with more frequent interspecific hybridization (Wiegleb and Kaplan 1998), increasing the possibility of chromosome changes. After physical mapping of rDNA in Potamogeton species, we found that 45S rDNA were discrepant intraspecifically and varied interspecifically.…”

“…Meanwhile, we noticed that a lower x = 7 chromosome number (2n = 14) was reported for a population of P. folisosus (Wiegand 1899) and P. perfoliatus (Moore 1973). Increasing identification of interspecific hybrids in Potamogeton demonstrated that the newly formed species were mostly from the x = 13 series species sets, reflecting hybridization speciation processing and construction from the other sides (Wiegleb and Kaplan 1998). Therefore, we propose that it is more cautious to discuss either x = 7 or x = 13 as representing a more ancient basic chromosome number, and more studies on the comparative morphology, geographic distribution, and comparative genomics and cytogenetics should be carried in the future.…”

“…2; i.e., P. pusillus, P. octandrus). An extensive variation of 45S arrays exists in the tetraploid species, which were the main composition of enrichment in Potamogeton groups (Wiegleb and Kaplan 1998). The number of these gene clusters present two (P. graminus, P. crispus), three (P. wrightii, P. distinctus, P. 9 intortusifolius), four (P.nodosus, P. perfoliatus), and six (P. natans, P.lucens), with size variation between the Fig.…”

Potamogeton ×jacobsii (Potamogetonaceae) from New South Wales, Australia – the first Potamogeton hybrid from the Southern Hemisphere

“…In their recent worldwide revision of Potamogeton including Stuckenia, Wiegleb and Kaplan (1998) listed 50 confirmed hybrids, all from the Northern Hemisphere. The number of identified Potamogeton hybrids has increased to more than 80 (Z.…”

When interspecific prezygotic barriers break down: hybridization between two Potamogeton species (P. wrightii and P. perfoliatus) and comparison of the artificial and natural hybrids

“…This knowledge makes the recognition of hybrids more accurate. Wiegleb and Kaplan (1998) made a worldwide revision of the genus and summarized 69 species and 50 well-confirmed hybrids around the world. More recently, with the aid of isozyme and molecular techniques, many putative hybrids have been identified (e.g., Hollingsworth et al 1995;Preston 1995b;Preston et al 1998;Fant et al 2001aFant et al , b, 2003Fant et al , 2005Iida and Kadono 2002;Fant and Preston 2004;Kaplan and Fehrer 2004;Kaplan and Wolff 2004;Whittall et al 2004;Kaplan 2007).…”