This study covers the whole of Togo. Togo is a country in West Africa, covering an area of 56,600 km². Ecologically, the country is divided into 5 ecological zones, discriminated mainly on the basis of climate, vegetation and relief (Ern 1979). The country usually has a humid to subhumid tropical climate, with rainfall ranges from 800 to 1600 mm per year. The country is crossed from south-west to north-east by the Atakora mountain range (also called Togo Mountains) which rises to 986 m at Mount Agou (Fig. 1). The rest of the territory consists of alluvial plains covered by a fairly dense network of mainly temporary rivers.

Figure 1.  

Study area (ecological subdivisions based on Ern (1979) and relief from SRTM2 scenes).

Existing collections and occurrence data

The herbarium specimens of Pteridophytes kept in the Lomé Herbarium (TOGO; herbarium acronym following Thiers 2018) were used for this study. In total, there are 223 specimens, which are judged insufficient to support this study. To this end, it was critical to carry out new collections in the field. In addition, the occurrences available at GBIF.org (2016) online database and in the works of Roux (2009) and Alston (1959) were taken into account.

Fieldwork and collection of new specimens

Complementary specimens were collected throughout the territory between March 2013 and August 2017 by K.E. Abotsi. The collection sites (Fig. 1) were chosen in order to increase the probability of encountering Pteridophytes and to cover the entire heterogeneity of the country. In all, 100 sites were selected in which collections were carried out, regardless of taxonomic affiliation.

For each gathering, 1 to 4 duplicates were collected depending on the availability of fertile plant material and the state of the population. A fragment of lamina was also collected and preserved in silica gel (Gaudeul and Rouhan 2013). Photos of the entire plant as well as close-ups for identification (fertile parts, venation, hairs, scales etc.) were taken to support the identification. A total of 869 georeferenced specimens were collected and are now kept in the Togo National Herbarium (TOGO). Duplicates were sent to the Herbarium of the National Museum of Natural History of Paris (P).

Study of collected specimen

Identifications of the newly collected specimens were carried out thanks to the reference specimens of TOGO and P herbaria (MNHN 2017) as well as the flora of Cameroon (Tardieu-Blot 1964), Benin (Akoègninou et al. 2006) and Mascarene Islands (Autrey et al. 2008). Species names were updated to follow the PPGI classification (PPGI 2016), and considering synonymies included in the literature or Tropicos (Missouri Botanical Garden 2018) or Roux (Roux 2009).

The collected specimens were studied on the basis of morphological characters (vegetative and reproductive), adapted from the list of descriptors proposed by Abotsi et al. (2015) for the Pteridaceae family. Information on the ecology and geographical distribution has been reported directly in the field.

Presentation of the checklist

The checklist is organised by suprageneric taxon according to the current classification (PPGI 2016). Only 3 representative specimens examined were cited in the checklist to avoid overloading the text.