{'fraction_non_alphanumeric': 0.03642987249544627, 'fraction_numerical': 0.024704007285974498, 'mean_word_length': 4.884125920964501, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 1, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
ORNAMENTAL PTERIDOFLORA FROM DAKAR (SENEGAL)

In Senegal, few scientific investigations have been done on ornamental pteridophytes, while the specific diversity of ornamental flora is becoming increasingly important due to the enhancement of several species belonging to different taxonomic levels. It is therefore important today to take an interest in this taxonomic group to contribute to a better knowledge of the ornamental flora of Senegal. More specifically, this work this present work aims to determine the taxonomic spectrum, the specific richness by family and the chorological spectrum of pteridoflore. Methodology and results: This study was carried out in 84 horticultural stations in the city of Dakar. In each site, a traveling inventory was carried out. Subsequently, the structure of the flora was analyzed. The results made it possible to identify 11 ornamental ferns, belonging to 5 genera united in 3 families. Among these species, none has been mentioned in the flora of Senegal. The Dryopteridaceae family is predominant with 72.72% of the species recorded. In addition, the genus Nephrolepis is the most diverse with 63.64% of the flora. In addition, this flora is dominated by pantropical species which represents 45.45% of the flora or 5 species in total.


INTRODUCTION
Senegal has significant specific richness with more than 3,500 plant species (Ba and Noba., 2001;MEPN, 2010). In this kingdom, Angiosperms (flowering plants) are best known. However, few scientific investigations have been made on lower plants, in particular the ornamental pteridophytes, while the expansion of floriculture in Dakar increases the number of taxa and mobilizes an important plant diversity consisting of both local species, that have been introduced for a very long time or recently (Dieng, 2014).
In addition, the cryptogamic flora presents a very important stake and interest for the country, both environmentally and economically. It is therefore important today to take an interest in this taxonomic group to contribute to a better knowledge of the ornamental Pteridological flora of Senegal. More specifically, this present work aims to determine the taxonomic spectrum, the specific wealth per family and the chorological spectrum.

Inventory and identification of taxa
The inventory was carried out in 84 stations by adapting the itinerant method, that is to say going around the plot and listing all the species that are cultivated there. For each of these plants, its botanical characters have been described on the spot and its vernacular name has been reported. Once in the laboratory, the botanical characters of each plant were compared to those described in the available documentation. After identifying each species, a corresponding scientific name was assigned to it and the description of its botanical characters completed. In addition, the species determination was carried out using: Flora (Hutchinson & Dalziel, 1954, 1963, 1972Hutchinson & al., 1958 ;Friedmann, 2011;LEjoly & al., 2010).

Samples of herbaria from the Department of Plant Biology of the Faculty of Sciences and
Techniques of the University Cheikh Anta DIOP in Dakar.
The nomenclature used follows the database managed at the Conservatoire et Jardin Botanique (CJB) in Geneva; this database is based on the important work of Lebrun andStork (1991-1997) and is accessible on the following regularly updated site: http://www.ville-ge.ch/musinfo/bd/cjb/africa/index.php?langue=fr The classification used is that of APG III (2009).

Analysis of the structure of the Pteridological flora
To analyze the Pteridological flora, the taxonomic spectrum, the specific richness by family and the Chorological Spectrum were determined.

 The taxonomic spectrum
For each species listed and identified, its scientific name (genus name + specific epithet) and its family have been attributed to it. Thus, the total number of species, genera and families of ornamental flora could be studied.

 The distribution of species by family
The distribution was made according to the formula below : For the development of the chorological spectrum, the species were classified according to their geographical origin. To do this, the information mainly comes from the flora of Hutchinson and Dalziel (1972), the illustrated flora of Berhaut . There are African Species (Af), Afro-American Species (Am), Afro-Asian Species (As), Afro-Malagasy Species (Ma), Afro-Malagasy and Asian Species (Mas), African and Mediterranean (Af-Me), African tropical species (AfT), and Pantropical species (Pt). For the evaluation and interpretation of the results, the percentage proportion of each biogeographic affinity is calculated by the following formula:

RESULTS AND DISCUSSION
 Taxonomic spectrum Table 1 gathers the list of ornamental ferns from Dakar. For each species, its presence or not in the flora of Senegal, its biological type and its geographical distribution were mentioned.
This work made it possible to identify in Dakar 11 species of ornamental ferns, belonging to 5 genera and 3 families (Tab1). Among these ferns, none has been recorded in the flora of Senegal.   This flora is dominated by the Dryopteridaceae family which brings together 72.72% of the fern species recorded, i.e. 8 species in total, followed by Polypdiaceae and Marsiliaceae with 18.18% (2 species) and 9.10% (1 species respectively (Tab. 2).

 Distribution of species by genus
The distribution of species by genus is shown in Table 3.
The most diverse genus is the Nephrolepis genus, which includes 63.64% of the species listed, or 7 species in total (Tab. 3). On the other hand, the genera with one (1) species group together in total 36.36% of the species. The representation of species according to their biogeographic affinities is grouped together in Table 4.
Our analysis shows that this flora is dominated by pantropical species which represents 45.45% of the flora, ie 5 species. The six (6) other biogeographical affinities together group together 54.55% of the flora (Tab. 4).

DISCUSSION
This work made it possible to identify in Dakar 11 ornamental ferns, belonging to 5 genera and united in 3 families. Compared to the Togolese ornamental flora, Radji & al., (2010) identified 20 species of ferns belonging to 6 genera and united in 4 families. This difference in the number of species could be explained by the fact that in the context of this work, only 84 nurseries were visited in Dakar, while in Togo Radji & al., (2010) made an exhaustive inventory in all the nurseries in Togolese towns. However, these results are similar to the work of Péne (2018) who identified 11 species belonging to 5 genera united in 3 families. This could be explained by the fact that the two studies were carried out in the same city. On the other hand, Baldé (2017) identified in the Kédougou zone 14 species divided into 8 genera and 6 families. Among the species identified by Baldé (2017), 9 are cited in the flora of Berhaut, unlike this present work where no species has been cited in the flora of Senegal. This could be explained by the fact that this study focuses on floriculture, which is one of the main vectors for the introduction of exotic plants throughout the world. This flora is dominated by the Dryopteridaceae family which includes 72.72% of the species listed. Unlike the Togolese ornamental flora where the Polypodiaceae family was predominant with 35% (Radji & al., 2010). Similarly, these results do not corroborate those of Baldé (2017) and Péne (2018) who showed that the dominant families are respectively those of the Pteridaceae (35.71%) and Davaliaceae (63.63%). The most diverse genus is the genus Nephrolepis which includes 63.64% of the listed species. This corroborates the work of Radji & al., (2010) who also showed that the genus Nephrolepis was more diverse with a rate of 25%. Among the species of this genus, we have Nephrolepis biserrata which is valued as a medicinal plant in Ivory Coast (Adou & al., 2014). Indeed, Nephrolepis biserrata is used as a medicinal plant in various forms of medicinal preparations in the fight against various pathologies such as: whitlow, wounds, boils, extracting thorns, fontanel, malaria, sickly and nonchalant baby and the reduction of large navels in children ( Adou & al., 2014). Nephrolepis exaltata, on the other hand, is considered to be an ornamental houseplant capable of absorbing formaldehyde and xylene (Langis and Kerry, 2012). The results also showed that this flora is dominated by pantropical species which represents 45.45% of the flora. This dominance of these pantropical species could be explained by the continental position and probably by the adaptation of these species to the bioclimatic conditions of the area (Noba & al., 2004).