New analysis of the endemic vascular plants of Algeria, their diversity, distribution pattern and conservation status

Abstract: In this study, we provide a new analysis on strict-endemic vascular plant taxa of Algeria and discuss their taxonomic diversity, geographical distribution and conservation status, based on a large literature review and our own field observations. Overall, 248 taxa (species, subspecies and varieties) are currently considered as Algerian endemics, from 41 families and 128 genera. They constitute about 6.3% of the total known flora of Algeria. The northern floristic regions are richer in endemic species: K1, K2, AS3, C1+C2 and O1 are by far the richest floristic regions for strict-endemic taxa, highlighting the importance of their mountain ranges. Most (59%) of the endemic plants have a narrow geographical distribution range (range-restricted). An overview of the IUCN conservation status of the Algerian endemics indicates that only 16 taxa (6.4%) are evaluated, out of which 5.6% of the taxa are threatened. Overall, 44% of the Algerian endemics are legally protected and 43% are included in the protected areas network. Finally, we focus on the shortfalls of knowledge that could orient further research on endemism data in Algeria. They concern taxonomic, chorological or conservation figures and above all the actual presence of the endemic species. It is, therefore, urgent to carry out targeted field expeditions in order to find and re-collect these species, most of which are strictly localized and have probably never been searched or found for 60 years to over a century. Citation: Meddour R Sahar O & Jur S 2023: New anal sis of the endemic vascular lants of Al eria their diversit distribution pattern and conservation status. – Willdenowia 53: 25–43. Version of record first published online on 21 March 2023 ahead of inclusion in April 2023 issue.


Introduction
The concept of endemism most used at present is referred to the restriction of the distribution of certain taxa to a distinct area (Laffan & Crisp 2003). Plant species are considered endemic to a country if they occur solely within its political borders (Gallagher & al. 2020). It is obvious that the endemics constitute the foremost group in terms of biodiversity and conservation of the flora (Millaku & al. 2016). Therefore, the number of endemic taxa in a country is one of the fundamental features of biodiversity (Hobohm 2014) and a first step for assessing the flora of that country (Treurnicht & al. 2017). A list of endemics to a country is of great relevance for conservation policy at both the national and local scales (Fois & al. 2022).
Algeria, which is an integral part of the biodiversity hotspot of the Mediterranean region , is recognized as an important centre of plant species diversity and endemism (Véla & Benhouhou 2007), facing a high level of human-induced threat (Quézel 2002). The vascular flora of Algeria is very diverse and offers an exceptional setting for the study of endemism and the distribution of its species.
The first attempt to describe the endemic vascular flora of Algeria was done by Quézel (1964). This author stated that the number of species endemic to N Algeria was estimated at 247, a rate of 8.6% of the N Algerian flora. According to Greuter (1991), Enríquez-Barroso & Gómez-Campo (1991) and Véla & Benhouhou (2007), Algeria has 320, 256 or 224 endemic taxa, respectively. According to the most recent data (Dobignard & Chatelain 2010, the Algerian vascular flora includes 3951 native taxa (species and subspecies), with 290 Algerian endemic species (6.5%).
Accounts on diversity of endemics in Algeria seem to be numerous, but there are some discrepancies about the exact number of endemic species. Comparing numbers with information from previous literature is always difficult, because some references are based on the number of species only, while others also consider infraspecific taxa and include endemic and subendemic species or only strict-endemics (Dobignard & Chatelain 2010. Otherwise, many subendemic taxa were formerly considered as strict-endemics to Algeria (Quézel & Santa 1962-1963, until their chorological status was changed according to new findings in neighbouring countries, specifically Morocco and Tunisia. The observed differences in these accounts are furthermore justified by the new contributions of knowledge on the Algerian flora and the consideration of taxa formerly overlooked or cryptic following taxonomic revisions (see, e.g., Romo & Boratyński 2010;Véla & al. 2013Vicente & al. 2016Vicente & al. , 2020. Statistics of this nature are complicated by ongoing taxonomic studies (Helme & Trinder-Smith 2006). After many recent findings regarding nomenclatural changes, mostly recombinations but also new taxa (Dobignard & Chatelain 2010, and geographical distribution changes, Algeria does not have an accurate and complete inventory relating to the endemic vascular plant taxa. Therefore, an updated checklist of Algerian endemics, including how many and which taxa are endemic and where they are found, is currently needed.
The aims of this study are hence to provide a new analysis of the strict-endemic vascular taxa of Algeria, to analyse their diversity, to interpret their distribution patterns and phytogeography within the Algerian floristic regions and to summarize their currently known conservation status.

Study area
Algeria is the largest country in Africa, with a total land area of 2,381,741 km². It is also the largest country bordering the Mediterranean Sea, with a coastline stretching along a length of 1355 km (Fig. 1). The Algerian territory is clearly divided into three geographical entities, the north or "Tell", restricted to the coastal plains and adjacent Tellian Atlas mountains, the "Steppe" considered in the widest sense and encompassing the High plateaus and the Saharan Atlas (both belonging to the Mediterranean region), and the south or "Sahara" (part of the Saharo-Arabian region). Therefore, its flora belongs to the Holarctic floristic kingdom (Quézel 1978).
Algeria is one of the most biodiverse countries in North Africa because of its unique biogeography with a transition between tropical and temperate climates (Véla & Benhouhou 2007), given its geographical position at the edge of the Mediterranean Sea. The interaction of the Mediterranean climate with the relief of the Atlas results in a strong environmental gradient, creating a north-south decrease in rainfall and an increase in dry season length, which determines huge changes in the structure and floristic composition of various types of vegetation linked to different ecological and bioclimatic zones (Meddour 2012). Therefore, considerable habitat diversity occurs throughout Algeria, explaining its high level of endemism and high plant diversity, with the presence of two major regional biodiversity hotspots, the "Kabylias-Numidia-Kroumiria" and the "Baetic-Rifean complex" (Véla & Benhouhou 2007).
Algeria has an important protected areas framework, encompassing ten national parks, two cultural parks and two natural reserves, oriented toward the conservation of habitats and their biodiversity (Benhouhou & al. 2018).

Data collection and analysis
In this work, we examined all available literature on the vascular flora of Algeria, and the main taxonomic web sources, to compile an updated checklist of strict-endemics to Algeria (or Algerian endemics) that occur only within the political borders of the country. The bibliographic research started with the Index synonymique de la flore d'Afrique du Nord (Dobignard & Chatelain 2010, where the Algerian endemics are labelled Alg*, which served as a priority source to select them. We matched these endemic plants with data available in the key da-assessed endemic plants have been classified at global geographical scope either into a threat category, according to the new categories (IUCN 2012), as Critically Endangered (CR), Endangered (EN) or Vulnerable (VU), or into the other categories as Near Threatened (NT), Data Deficient (DD) or Least Concern (LC).
Algerian endemic taxa protected by the national legislation in Algeria are compiled according to the List of non-cultivated plant species protected throughout Algeria, set by Executive Decree no. 12-03 of 4 January 2012 (JORA 2012), after carefully checking the nomenclatural synonymy issues.
Otherwise, we highlight endemic taxa that are already benefitting from protected area status in Algeria, such as national parks (NP), natural reserves (NR) and cultural parks (CP), formerly classified as national parks until 2011. Algerian Cultural Parks (CPs) are recognized as "Other Effective Area-Based Conservation Measures" (OECMs), which offer an excellent opportunity to acknowledge effective long-term biodiversity conservation that takes place outside currently designated protected areas (IUCN 2020).

Diversity and taxonomic analysis
The Algerian endemic vascular flora includes 248 taxa (distributed among 174 species, 72 subspecies and 2 varieties) (see Appendix 1), representing almost 6.3% of the native flora of Algeria. They belong to a large number of 128 genera and 41 families. The distribution of endemic species in Algeria is uneven according to the 41 families (Fig. 3). Twenty families, containing three or more endemic taxa each, collectively contribute 90% of the endemic taxa in Algeria: Asteraceae (20% of endemics), Fabaceae (10%), Caryophyllaceae (9%) and Lamiaceae (8%) are the best-represented families, followed by Brassicaceae (7%), Papaveraceae (7%) and Poaceae (6%). Then, four families include two taxa each, and the remaining 17 families are represented by only one endemic taxon each. Otherwise, there is a weak correspondence between species-rich plant families and endemism. Some larger families contribute more endemic species to the flora of Algeria, while others contribute few endemics, relative to their dominance in the flora. The case of the Poaceae, which is the second most species-rich plant family, illustrates this fact; it occupies only the seventh position in terms of number of endemics. Besides, certain families are significantly over-represented, such as Papaveraceae, contributing a high proportion of endemics relative to their contribution to the overall flora (Fig. 3).
Endemism appears to be particularly dispersed within the genera present in Algeria (Table 2). Indeed, out of 128 genera containing endemic taxa in Algeria, only 15 of them have four or more taxa each, 11 gen-tabases, such as the African Plant Database (APD 2022) and the online eflora du Maghreb (eflora Maghreb 2022), which specify the endemic status of all plants present in Algeria. We cross-checked the information with data from the Euro+Med PlantBase (Euro+Med 2022) and the Plants of the Word Online database (POWO 2022), which allow confirmation of endemism, in particular the exclusive presence in Algeria of the taxa selected. We have only retained the taxa (species, subspecies and varieties) considered by all the sources mentioned above as strict-endemics. Plants no longer considered as endemic to Algeria, for taxonomic or chorological reasons (Algerian-Tunisian, Algerian-Moroccan endemics or other subendemics), were therefore excluded (Table 1). Likewise, hybrid species exclusive to Algeria are not recorded in the present analysis. A refined dataset was created at the end of this sorting.
The taxonomic nomenclature of taxa (with their authorities) was revised, and accepted names of species and infraspecific taxa follows the African Plant Database (APD 2022), except in the case of Cyclamen repandum var. baborense Batt. ex Debussche & Quézel, where the name has been updated according to POWO (2022). For angiosperms, plant family circumscription follows APG IV (2016).
The distribution of endemic taxa in the phytogeographical subsectors (hereafter "floristic regions") of Algeria was mainly documented according to the existing literature (Battandier & Trabut 1888-1890, 1895, 1905Maire 1952Maire -1987Quézel & Santa 1962-1963Ozenda 2004), herbarium specimen label data (cf. eflora Maghreb 2022) and our own field surveys. In Algeria, 20 floristic regions were defined based on the distribution of the endemic plants in relation to the local climates, geology and geomorphology, and according to different vegetation types (Quézel & Santa 1962-1963Meddour 2012). Among these floristic regions, 15 northern ones are under Mediterranean influence, while five others are entirely Saharan (Fig. 2).
We made the deliberate choice not to use the rarity index as established by Quézel & Santa (1962-1963, because it is very outdated and far from any modern significance. One of the three attributes defining rarity is the size of the species range (large vs small) (Rabinowitz 1981). In this sense, the distribution analysis of endemic flora will allow us to identify the "range-restricted" taxa, i.e. present in only one floristic region within Algeria. In the same way, Fennane & Ibn Tattou (1999) considered the taxa present in one (or two) phytogeographic divisions of Morocco as "rare".
With regard to the conservation status of the Algerian endemics, there is yet no national Red List established in line with the IUCN criteria. The data derived from IUCN database (IUCN 2022) are used to determine what proportion of the endemic plant species have an assessment of their extinction risk, although this status has not been assessed for all taxa, nor specifically for Algeria. The Table 1. List of taxa previously considered as Algerian endemics (Dobignard & Chatelain 2010 but now no longer considered as Algerian endemics, with reasons for their exclusion. Subspecies previously distinguished no longer recognized and species also reported from Morocco (APD 2022) era (Anthemis L., Centaurea L., Crepis L., Festuca L., Fumaria L., Genista L., Ononis L., Rupicapnos Pomel, Salsola L., Silene L. and Teucrium L.) have five endemic taxa or more and only two of these genera have more than ten (Rupicapnos and Silene). The genus Silene is by far the richest in the Algerian endemic flora, with 12 strict-endemic species. Algeria is therefore identified as a centre of endemism for these two genera. The greater part of the genera (103 genera, 81%) are represented by only one or two endemic taxa each. In addition, generic endemism is shown in Algeria by the presence of two exclusively Algerian genera, namely Agropyropsis (Batt. & Trab.) A. Camus (Poaceae) and Otocarpus Durieu (Brassicaceae).

Location of endemic species according to the floristic regions
There is considerable variation in the number of endemics within the floristic regions (from zero to 63 taxa) (Fig. 4). Out of the 20 floristic regions in Algeria, ten regions harbour at least 20 endemic taxa and five regions (K2, K1, AS3, C1+C2, O1) include more than 30 endemics each. Altogether, a high number of Algerian endemics (147 or 59%) are range-restricted, i.e. narrowly localized and known from only one floristic region. These endemics are observed especially on the hills of Oran (O1: 24 taxa), the forests of Small Kabylia (K2: 20), the summits of the C Sahara (SC: 15), the Aurès massif (AS3: 12) and the mountains of the W Tell (O3: 11). In all these floristic regions, a large portion of the endemic flora is constituted of these range-restricted taxa, which greatly individualize them phytogeographically.

Conservation status and protection of endemics in Algeria
Concerning their conservation status, 90 Algerian endemic taxa were previously included in the 1997 IUCN Red List of threatened species and classified as follows: 24 taxa Endangered (E), 16 Vulnerable (V), 45 Rare (R) and 5 Indeterminate (I), according to the pre-2001 IUCN categories (cf. Walter & Gillett 1998 (14), El Kala NP (13) and Gouraya NP (12); and also Ahaggar CP (12) in the C Sahara. However, endemic species occur in Algeria everywhere, so there are many such species (141 taxa) outside the existing protected areas network. Altogether, 167 taxa (67%) are protected in Algeria by being on the national Red List and/or by overlapping partially or completely the protected areas network. Therefore, 81 taxa are without any protection, from which 45 are range-restricted and deserve urgent protection, at least national Red-Listing, e.g. Silene auriculifolia Pomel (see Table 3 and Appendix 1).
Algerian plant species. Therefore, the globally assessed endemic flora of Algeria is limited to 16 endemic taxa (6.4%), out of which 14 are threatened (5.6%) and listed as follows: five taxa Critically Endangered (CR), three Endangered (EN), two Vulnerable (VU), four Data Deficient (DD) and two Least Concern (LC) (Table 3).
Overall, the law protects only 110 endemic taxa (44% of the total), which are included in the List of non-cultivated plant species protected throughout Algeria. The remaining endemics are not yet legally protected. We recommend inclusion of the range-restricted endemic taxa in the national list of protected plants, in particular the threatened ones (noted by an asterisk in Table 3).
Of the 248 endemic taxa, 107 (c. 43%) are already benefitting from protected area status. Indeed, the protected areas network overlaps totally or partially the distribution areas of these endemics, especially the National

Taxonomic diversity
Among the Mediterranean countries, Algeria, in spite of being a desertic country over 84% of its territory, occupies the seventh position in terms of richness in number of plant taxa (Quézel 1995) and the second position in North Africa, with 3951 native taxa (Dobignard & Chatelain 2010. With 248 endemic taxa (6.3% of the overall flora), strict-endemism in Algeria is slightly higher than in other North African arid countries, such as Libya (6%), Tunisia (2.6%) and Egypt (2.3%), but substantially lower than in Morocco (18%), which is recognized as having the highest plant diversity in North Africa (Dobignard & Chatelain 2010Abdelaal & al. 2018). Likewise, in comparison with some European countries characterized by a Mediterranean climate, diverse topography and islands, such as Italy (13.4%) and Greece (15.6%) (cf. Rankou & al. 2013), the number of endemics in Algeria is very much lower. Moreover, according to Aedo & al. (2013), endemism reached 21% in the Spanish flora (the Canary Archipelago excluded).
The preponderance of Asteraceae (20%), followed by Fabaceae, Caryophyllaceae, Lamiaceae and Brassicaceae, which support a speciose number of endemic taxa, is remarkable in this endemic flora. This is not surprising, because families with the largest number of endemic plants are the largest families of Algeria (Quézel 1964(Quézel , 1978Dobignard & Chatelain 2010. This is likewise the case in Morocco (Fennane & Rejdali 2019) and the overall Mediterranean Maghreb (Quézel 2002). Nevertheless, the Poaceae, which is the second largest family, falls unexpectedly outside the top ten families for endemics. It is significant to note that, far from Alge-ria, Darbyshire & al. (2019) made the same observation about the endemic flora of Mozambique.
The Genera Anthemis, Centaurea, Crepis, Festuca, Fumaria, Genista, Ononis, Rupicapnos, Salsola, Silene and Teucrium are the richest in endemic species (at least four endemic species per genus). This is also the case in Morocco (Rankou & al. 2013) and the whole of North Africa (Quézel 1978(Quézel , 2002, except for the genera Rupicapnos and Salsola. The case of the critical genus Rupicapnos is probably the most obvious (Quézel 1978), because it has the highest endemic diversity (11 taxa) in Algeria. Actually, species concepts and the number of species recognized in Rupicapnos vary considerably between authors, and this genus has been subject of very different taxonomic treatments. Pugsley (1919) already recognized some 30 species in North Africa, nearly one per locality, while Maire (1952Maire ( -1987 and Quézel & Santa (1962-1963 kept only three collective species in the genus. Then, following Lidén (1986), Dobignard & Chatelain (2010 retained for Algeria 17 taxa (seven species and ten subspecies), including 11 endemics, against only five taxa (including only one endemic) in Morocco. Therefore, this Ibero-Maghrebian (Spain, North Africa) genus is most developed in Algeria, its centre of diversity (Battandier 1922a).
Widely distributed in arid and semi-arid regions of the world (ElNaggar & al. 2022), the genus Salsola is represented in Algeria by 11 species and varieties (Quézel & Santa 1962-1963 to 22 species and subspecies (Dobignard & Chatelain 2010. The number of endemics has in the meantime increased from one Algerian endemic (Salsola cruciata L. Chevall. ex Batt.) to seven strict-endemic species, following the work of Botschantzev (1975). However, the genus Salsola, due to the physical similarity between many species, is regarded as exceedingly difficult and is frequently overlooked (Murshid & al. 2022). Indeed, these Algerian endemic taxa have remained cryptic and unknown, as they have never been cited afterward, notably by Le Houérou (1995) in the steppe region, nor by Ozenda (2004) in the Algerian Sahara. They are to be actively sought out in the field and require a taxonomic revision. Otherwise, generic endemism is manifested in Algeria by the presence of two exclusively Algerian genera, namely Agropyropsis (Poaceae) and Otocarpus (Brassicaceae), both monospecific and having a restricted distribution (Quézel 1964(Quézel , 1978.

Distribution patterns, chorology and regional hotspots
The distribution of endemic plant taxa in Algeria is not random, and not all areas are equally rich in endemic species, as previously shown by Quézel (1964). Within the floristic regions of Algeria, the Oran sector and Kabylia-Numidia sector (Quézel & Santa 1962-1963 are indicated as the most important centres of endemism, a well-known fact commented on previously by Quézel (1964), Enríquez-Barroso & Gómez-Campo (1991) and Table 2. Ranking of larger genera that contribute four or more endemic taxa to Algeria. nET: number of endemic taxa; %ET: % of endemic taxa (n = 248).

Rank Genus
Family nET %ET  Véla & Benhouhou (2007). According to these authors, the most remarkable floristic regions for endemism are the Oran coast (O1), followed by the Small Kabylia (K2) and the Great Kabylia (K1). However, when considering the strict-endemism, the floristic regions with the highest number of endemics are the same, but their ranking is different in the two cases. We have recorded important centres of endemism in Algeria, in this rank: K2 including Babors (25%), K1 including Djurdjura (20%), AS3 including Aurès (17%), C1+C2 including the Belezma and Hodna chains (16%) and lastly the Oran coast O1 (c. 16%). The latter is especially rich in Algerian-Moroccan endemics, as shown by Medjahdi & al. (2009). The high-altitude flora of the Atlas Mountains of Algeria is recognized to be rich in endemics, including orophytes (cf. Quézel 1964Quézel , 1957Quézel , 1978, as well as in Morocco (Neffati & al. 1999;Rankou & al. 2013). This high richness in endemics is probably linked to high rainfall and short dry season incidence in these areas (Fennane & Ibn Tattou 1999). It is likewise the case for the high mountains of the Algerian C Sahara (SC: Ahaggar, Tassili n'Ajjer) (Ozenda 2004), which harbour a noteworthy rate (7%) in a desertic environment. These mountains (highest peak: Mount Tahat, 2908 m, Ahaggar) are cooler and wetter than other S Saharan regions of the Maghreb (Walas & Taib 2022). The higher number of endemic plant taxa in mountainous (as well as coastal) regions is a common pattern observed in the Mediterranean Basin (Verlaque & al. 1997;Abdelaal & al. 2020;Walas & Taib 2022) and other mountainous areas, such as Iran (Noroozi & al. 2018).
The analysis of distribution patterns of richness in endemic taxa in Algeria supported that the areas richest in endemic taxa match well the regional hotspots (cf. Véla & Benhouhou 2007) and putative refugia (Médail & Diadéma 2009) already described in Algeria. These areas are of high priority to preserve plant diversity (Myers & al. 2000) and to promote the sustainable management of these critical sites and their species (Darbyshire & al. 2019).
Furthermore, this analysis allows the most narrowly distributed species to be highlighted: the 147 range-restricted endemic taxa (59%). They are sometimes sporadically distributed, form small populations in the wild (Carbutt & Edwards 2006;Libiad & al. 2020) and in some cases are known from a single population of few individuals (e.g. Atractylis caerulea Batt. and Tricholemma breviaristatum (Barratte) Röser). In the Mediterranean region, Greuter (1994) similarly demonstrated that a remarkable number of narrow endemics reflects plant species presenting small mean distributional ranges. Their conservation needs to be prioritized (Laffan & Crisp 2003).

Conservation status, redlisting and protected areas
With regard to their conservation status, new evaluations by IUCN (2022) in Algeria are very scarce, and the   On the other hand, many areas, such as the Aurès massif and the Oran coast (except the Habibas Islands and Lindlès Cape, recently established as natural marine reserves), do not have any designated protection, despite hosting a great number of endemic taxa (14 and 27, respectively). Both these regions are of high priority for establishing as additional protected areas. However, the Oran coastal region has undergone much greater anthropization, compared to Aurès, where mountain habitats are more preserved. It therefore requires priority conservation action.
Even so, knowledge on Algerian endemic plants is not well documented and there is insignificant data on their threat status, distribution or even their existence (Miara & al. 2018a). Algerian endemic plants are insufficiently known, and most of them have never been observed since their discovery 60 years to over a century ago. For others, the type material has not yet been found in a herbarium. In particular, taxa known only from the type locality (or the type specimen) are to be underlined: Artemisia alba subsp. kabylica (Chabert) Greuter has not been re-collected since the type was gathered at Ait Bou Youcef (Kabylia) in 1888 (Ouyahia 1989).
Asyneuma rigidum subsp. aurasiacum (Batt. & Trab.) Damboldt was gathered in Sgag (Aurès) in 1892 but was globally assessed endemic flora of Algeria is limited to only 16 endemic taxa (6.4%), of which 14 are threatened. Therefore, 93.6% of Algerian endemic taxa are as yet Not Evaluated (NE) by IUCN (2022). According to Gallagher & al. (2020), 67% of country-based endemic species do not have a completed threat assessment, particularly in North Africa. Effectively, the task of assessing the conservation status of the endemics is a difficult one, because insufficient data are available to evaluate many endemic species, such as estimates of population size, distribution range, number of locations, etc. (Carbutt & Edwards 2006). This is especially the case in Algeria.
The list of protected plants in Algeria (JORA 2012) includes 452 taxa. However, strict-endemic plants are underrepresented in this list, because it contains only 110 endemic taxa (44% of the endemic flora). Therefore, the national legislation does not protect a great number (138) of strict-endemic taxa. Additionally, 107 taxa (43%) are already benefitting from indirect protection status, because they are by chance included in the national network of protected areas. In order to complete the National Red List of plants, we must add all the range-restricted endemic taxa, especially those that are not present in protected areas (46 taxa), mainly the threatened ones (see Table 3 and Appendix 1). Nevertheless, it would not be reasonable to declare all these taxa extinct without having searched for them in a targeted way. Some of these allegedly extinct endemics (Faurel 1959;Mathez & al. 1985), not seen since after their first description in Algeria, have actually been rediscovered in their loci classici or new sites. We have to mention Allium seirotrichum Ducell. & Maire (temporarily considered as a synonym of A. trichocnemis J. Gay) (Khedim & al. 2016), Anthemis maritima subsp. bolosii Benedí & Molero (Sakhraoui & al. 2021), Crepis arenaria (Pomel) Pomel subsp. arenaria (Gordo & al. 2021 (Quézel 1953) and has never been recollected since.
Atractylis caerulea is known from only three collections in 1919 at the south of Sersou (Quézel & Santa 1962-1963 and has not been re-collected since. Erodium guinochetianum Guitt. is known from only one location (Tiaret) and has never been re-collected since 1963 (Guittonneau 2017).
Vulpia obtusa Trab. has never been re-collected since its description in 1902. Little is known about this species from Lake Oubeira (El Kala), and Maire  had seen no material, despite searching in the Trabut herbarium (Stace 2022).

Author contributions
RM contributed to the research conception, acquisition of data, analysis and interpretation, prepared the manuscript and reviewed the final draft. OS contributed to the preparation of the list of endemic taxa and reviewed the final draft. SJ contributed to the improvement of the English language, provided additions and comments and revised the final draft.
As a result, the data shortfalls on endemic plants do not only concern chorological, biological or taxonomic data, but above all the real presence of these species. It is therefore urgent to carry out targeted field expeditions, on the scale of the entire national territory, in order to find and re-collect these taxa, most of which are strictly localized, either in their classic localities or in new locations.

Conclusion
The level of plant endemism in Algeria is high, and it is treated here within a conservation framework to draw attention to the local and global significance of its biodiversity. We collected data from literature including Floras, herbaria and our expertise to compile the most comprehensive dataset on endemic vascular plants to Algeria. We have tried to be exhaustive, but our intention is to maintain this working list and publish additions as taxonomic revisions over time occur. This will require the periodic updating of our checklist. There is likewise a need to update plant statuses (distribution, biology, threats), in particular those threatened and range-restricted endemics that occupy a place of first importance in conservation programs. This study not only provides a picture of the endemic flora to Algeria, but it also identifies shortfalls in knowledge on which future research efforts could focus. In this case, the search for taxa that have not been seen for a very long time is regarded as an urgent task.