Taxonomy, distribution and nomenclature of three confused broad-leaved Potamogeton species occurring in Africa and on surrounding islands

Abstract

A taxonomic revision of broad-leaved Potamogeton species ascribed to the ' P. schweinfurthii-thunbergii complex' occurring in Africa and on surrounding islands is presented. Three species, P. nodosus , P. richardii and P. schweinfurthii , are recognized in the African mainland. The widespread species P. nodosus has been widely overlooked in sub-Saharan Africa. It is recorded here for the first time from eight countries of tropical and southern Africa and from six surrounding islands. The distribution of P. richardii is critically revised and the species is recorded for the first time from Cameroon, Swaziland and Madagascar. P. schweinfurthii is recorded for the first time from Algeria, Tunisia, Burkina Faso and Niger. The nomenclature of all three species is revised. Lectotypes are designated for six names. All original material of the name P. thunbergii Cham. et Schltdl. actually belongs to P. nodosus Poir. The correct name for the East and southern African species called ' P. thunbergii ' is P. richardii Solms. The lectotype of P. schweinfurthii designated by Dandy proved to be P. nodosus . A new type is therefore proposed for the species generally named P. schweinfurthii and the name itself is proposed for conservation. The morphology and stem anatomy of P. nodosus , P. richardii and P. schweinfurthii are described. In spite of some overlaps in the morphological variation in their vegetative characters, a detailed analysis of the variation patterns and instructions for reliable identification are given. The distributions of all three species are described, based solely on reliably identified specimens, many of which were also examined anatomically. Distribution maps are provided.

Ribosomal ITS sequences and plant phylogenetic inference

“…In particular, the semi-amplexicaul bases are clearly derived from P. perfoliatus, the only species occurring in Africa and characterized by amplexicaul leaves. This is an universal character of all P. perfoliatus hybrids (see, e.g., Dandy, 1975;Preston, 1995;Fant & Preston, 2004;Kaplan & Fehrer, 2004Kaplan, 2005Kaplan, , 2007. The hybrid is also more similar to P. perfoliatus in its sessile leaves, the shape of the leaf apex, short persistence of stipules and size of the inflorescence.…”

The Flora of Chad: a checklist and brief analysis

“…Whenever available, specific studies have been taken into account, e.g. Romo and Boratyński (2011) for genus Luzula (Juncaceae), Anthelme et al (2001) for Ferns in Sahara Mountains, Montes-Moreno et al (2010) and Qaiser and Lack (1986) for the genus Phagnalon , Kaplan and Symoens (2005) for Potamogeton , Beier (2005) for Fagonia .…”

Potamogeton×exilis (P. alpinus×P. natans), a new hybrid pondweed from Finland

“…Morphological observations were made mainly on recently collected and carefully prepared herbarium material. Abundant morphological data compiled for previous studies (Wiegleb and Kaplan 1998, Kaplan 2001, 2002b,c, 2005b, 2010a,b, Kaplan and Wolff 2004, Kaplan and Symoens 2004, Kaplan and Symoens 2005, Kaplan and Fehrer 2009) and available in modern taxonomic revisions (Preston 1995a, Preston 1995b, Bobrov and Chemeris 2006) were also considered in order to cover the morphological variation of the respective species as completely as possible. Rare extremes were excluded from the quantitative data.…”