﻿Cytotaxonomic investigations on species of genus Narcissus (Amaryllidaceae) from Algeria

﻿Abstract This paper provides new cytotaxonomic data on the genus Narcissus Linnaeus, 1753, in Algeria. Populations of seven taxa, N.tazetta Linnaeus, 1753, N.pachybolbus Durieu, 1847, N.papyraceus Ker Gawler, 1806, N.elegans (Haworth) Spach, 1846, N.serotinus sensu lato Linnaeus, 1753, including N.obsoletus (Haworth) Steudel, 1841, and N.cantabricus De Candolle, 1815, were karyologically investigated through chromosome counting and karyotype parameters. N.tazetta and N.elegans have the same number of chromosomes 2n = 2x = 20 with different karyotype formulas. Karyological and morphological characteristics, confirm the specific status of N.pachybolbus and N.papyraceus, both are diploids with 2n = 22 but differing in asymmetry indices. The morphotypes corresponding to N.serotinus sensu lato show two ploidy levels 2n = 4x = 20 and 2n = 6x = 30 characterized by a yellow corona. Some hexaploid cytotypes have more asymmetric karyotype with predominance of subtelocentric chromosomes. They are distinguished by orange corona and may correspond to N.obsoletus. Other cytotype 2n = 28 of N.serotinus was observed in the North Western biogeographic sectors. N.cantabricus was found to be diploid with 2n = 2x = 14, which is a new diploid report in the southernmost geographic range of this polyploid complex.


Introduction
The extended family of the Amaryllidaceae J. S. Hilaire, 1805, is one of the largest families of Asparagales. Among the subfamily Amaryllidoideae Burnett, 1835, species of tribe Narcisseae H.C. Lam et De Candolle, 1806, distributed in about 11 sections (Zonneveld 2008;Marquez et al. 2017), constitute the most attractive group of plants due to their botanical characteristics, evolutionary trends, biochemical properties and ornamental interests. Despite the well-known phylogenetic relationships at the generic level (Santos-Gally et al. 2012;Marques et al. 2017), many questions remain still unclear at the specific level. This is probably due to the lack of unequivocal diagnostic characters, a likely consequence of a variation driven by a deeply reticulated evolutionary history with their high ability to hybridize (Rønsted et al. 2008;Aedo et al. 2013;García et al. 2014;López-Tirado 2018;González et al. 2019). Moreover, species of tribe Narcisseae, constitute an enigmatic model of karyotype evolution in terms of chromosome numbers, base number and origin of the polyploids. This is particularly true for species of genus Narcissus Linnaeus, 1753, which with about fifty species, exhibit a high variation in chromosome numbers ranging from 2n = 10 to 72 with occurrence of aneuploidy and polyploidy (Fernandes 1975;Brandham and Kirton 1987;Zonneveld 2008;Díaz Lifante et al. 2009;Sun et al. 2015). Many chromosome numbers have been reported and different basic numbers assumed but still unclarified. The most reported basic chromosome numbers in the literature were x = 5, x = 7, x = 10 and x = 11. In Algeria, species of genus Narcissus belong to three sections: Tazetteae De Candolle, 1806, Serotini Parlatore and Bulbocodii DC.
In the section Tazetteae, four species were recognized in the Algerian flora (Maire 1959). For this section, the common cited chromosome number was 2n = 2x = 20 (Fernandes 1975;Brandham and Kirton 1987) especially for Narcissus tazetta Linnaeus, 1753, the most karyologically studied species. This species is widely distributed in the Mediterranean region, with the South Iberian Peninsula and Morocco as the center of diversity (Santos-Gally et al. 2012), and could reach the southern-west Asia, China and Japan (Hong 1982). These plants are characterized by a striking morphological variability expressed at the shape and color of corona and perianth divisions (Jones et al. 2008;Mifsud and Caruana 2010;Koopowitz et al. 2017). Comparison of the genome size by flow cytometry within N. tazetta had led Zonneveld (2008) to assume that this species is tetraploid with base number x = 5. In this same section, Narcissus elegans (Haworth) Spach, 1846, is also considered as tetraploid with 2n = 4x = 20 according to studies on genome size (Zonneveld 2008), in situ hybridization (Díaz Lifante et al. 2009) and phylogenetic analyzis (Marques et al. 2017). In section Serotini, the base number is also x = 5 and concerns Narcissus serotinus Linnaeus, 1753, sensu lato, in which three cytotypes have been observed: diploid (2n = 10), tetraploid (2n = 20) and hexaploid (2n = 30). These cytotypes were observed in populations respectively from the Iberian Peninsula and Morocco (Fernandes 1968;Aedo 2013), Sicily (Garbari et al. 1973;Phitos and Kamari 1974) and Central Italy (D'Amato 2004). The geographic range of the type N. serotinus would cover the Iberian Peninsula and northern Morocco. The presence of this taxon in Algeria, was recorded by all the botanists in XIX and XX centuries (Munby 1847;Battandier and Trabut 1895;Maire 1959;Quézel and Santa 1962) but remains doubtful and raises controversy as underlined in the Red List of IUCN (Juan Vicedo et al. 2018).
Similar ambiguity arose in Algeria for Narcissus cantabricus De Candolle, 1815, of the section Bulbocodii. This species has been considered first under N. bulbocodium subsp. monophyllus (Durieu) Maire, 1931, then later, as a distinct species (Quézel and Santa 1962). N. bulbocodium is distinguished by a large polyploid series ranging from diploid 2n = 14 to octaploid 2n = 72 (Fernandes 1963(Fernandes , 1968Zonneveld 2008;Marques et al. 2017) while N. cantabricus was known as diploid and tetraploid in Spain and Morocco.
Despite its central biogeographic position in the southwestern Mediterranean region, Algeria is characterized by an obvious lack of cytotaxonomic data leading to controversies about status and circumscription of many taxonomic units particularly within the Asparagales (Hamouche et al. 2010;Azizi et al. 2016;Khedim et al. 2016;Boubetra et al. 2017). Unfortunately, genus Narcissus is little known and poorly studied in our country.
The aim of this study is to fill the gap in the karyological data that links between the floras of the western Mediterranean region. It focuses on the main taxa of genus Narcissus recognized in the flora of Algeria, namely N. tazetta, N. elegans, N. serotinus sensu lato, N. pachybolbus, N. papyraceus and N. cantabricus. Chromosomal counting, structural parameters of the karyotype and the geographical distribution of the polyploidy have been done for each species. Karyological data were linked to morphological and chorological criteria in order to improve taxonomic and nomenclatural knowledge on the genus Narcissus in Algeria.

Sampling and plant identification
Plant material used in this study consists of 32 natural populations of genus Narcissus sampled in contrasting ecological conditions along the east-west biogeographic gradient of the northern Algeria (Table 1). Systematic determinations were made using the main Algerian floras (Munby 1847;Trabut 1895, 1902;Maire 1959;Quézel and Santa 1962) as well as floras from the Iberian Peninsula (Aedo 2013), from Morocco (Fennane et al. 2014), and from Tunisia (Le Floc'h et al. 2010). Status of the species and synonyms have been checked on the two main specialized websites, World Check List of Selected Plant Families (Govaerts 2015) and African plant data-  Quézel and Santa (1962). ‡ Nomenclature from Maire (1959), Quézel and Santa (1962) and Dobignard andChatelain (2010-2013). *N. serotinus sensu lato includes also N. obsoletus.

Chromosome preparations
Chromosomal analysis was based on metaphase plates of root-tip cells from cultivated bulbs. Young roots (6-10 mm long) were pre-treated with 1% colchicine for 5-6 hours at room temperature, then fixed in ethanol-acetic acid (3:1) for 48 hours and conserved at 4 °C in ethanol 70°.The protocol was adapted from the Feulgen method (Jahier et al. 1992). The root-tips were hydrolysed in 1N hydrochloric acid for 7-12 min at 60 °C before stained with Schiff's reagent in darkness for 1-2 hours. The squash was made in a drop of 45% acetic acid or carmine acetic. Metaphase plates were examined with a Zeiss Axiostar-Plus Microscope. Cells with good spreading of chromosomes were photographed.

Karyotype analysis
Karyomorphometric measurements and the homologous chromosome ordering were made using the KaryoType Software 2.0 (Altınordu et al. 2016). Chromosomes are described according to the nomenclature of Levan et al. (1964) based on the arm ratio (r = long arm / short arm) and the centromeric index (CI% = short arm / long arm + short arm × 100): metacentric (m), submetacentric (sm), subtelocentric (st) and telocentric (t). Ideograms were drawn from at least 5 well-spread metaphase plates of different individuals. Karyotype asymmetry indices were estimated following the proposal of Peruzzi and Eroğlu (2013). The intrachromosomal asymmetry index is represented by the mean centromeric asymmetry MCA = A × 100, where A is the average ratio of long arm-short arm/long arm + short arm (Watanabe et al. 1999). The interchromosomal asymmetry index is the coefficient of variation of chromosome length CV CL = A2 × 100 (Paszko, 2006) where A2 is the standard deviation of chromosome length/mean chromosome length (Romero Zarco 1986).
The coefficient of variation of the centromeric index CV CI = SCI / X -CI × 100 is the ratio between the standard deviation SCI and the mean centromeric index X -CI (Paszko 2006).

Morphological analysis
In order to link karyological data to morphological relationships between the studied species, multivariate analyses were carried out using the diagnostic descriptors of vegetative and reproductive parts, some from personal observations (Table 3). Principal Component Analysis (PCA) were performed using the program R Software 4.1.0 (2021).

Results
Chromosome numbers, ploidy level and characteristics of the karyotypes of the examined populations are summarized in Table 4. Comparisons of chromosome numbers from this study with those reported in the literature are summarized in Table 5. Representative metaphases and ideograms are shown in Figs 2, 3 respectively. Following the karyological data, we carried out morphological analysis for the studied taxa i.e., N. tazetta, N. elegans, N. pachybolbus, N. papyraceus, N. serotinus and N. cantabricus. Morphological analyses aim to highlight on interspecific variability in relation to karyological characteristics of the species. This species has many heterotypic synonyms. It is widespread in the north of Algeria and shows a high polymorphism with regard to the color of the perianth and corona (Fig. 1). The somatic chromosome number is generally 2n = 20 ( Fig. 2A) and constant in all the karyologically examined populations (Table 4). Sometimes 1 to 2 supernumerary chromosomes have been observed such as in populations of Sidi Khélifa (Fig. 2B, C), and Oued Djenane (Fig. 2D). Three different cytotypes were observed ( Table 3). The karyotypic formula 10sm + 10st was found in most of populations. Two other cytotypes concern populations located towards the east, Oued Djenane and Tabarka, with 2m + 8sm + 10st and 4m + 10sm (2sat) + 6st, respectively. The last two karyotypes are distinguished by a lower asymmetry indices MCA, 38.85 and 46.68 respectively, versus 50.27 for the remain populations. Satellites were observed in population of Tabarka only (Fig. 2E), which is characterized by a relative smaller total haploid length (THL = 114.75 μm).

Narcissus papyraceus Ker Gawler, 1806
≡ Narcissus tazetta subsp. papyraceus (Ker Gawler) Baker, 1888 This species has long been confused with the spontaneous N. pachybolbus due to strong similarities in the flower. N. papyraceus is an ancient cultivated species locally naturalized in Algeria. Two populations were found in the cemeteries of Algiers at Bologhine (ex. Saint Eugène) (Fig. 2G) and El Alia. Both populations show 2n = 2x = 22 chromosomes with the same karyotype formula 6m (2sat) + 12sm + 4st (Table 3). The karyotype of this species differs from that of N. pachybolbus by the presence of satellites on the 3 rd metacentric pair. For this taxon, the coefficients of variation of the length of the chromosomes (CV CL = 37.62) as well as the centromeric index (CV CI = 29.57) are lower. Despite their morphological similarity, the THL of N. papyraceus is closer to that of N. tazetta than that of N. pachybolbus (Table 3, Fig. 3E).

Discussion
In order to link karyological and morphological data of the Algerian species, Principal Components Analysis (PCA) were performed on the basis of the main taxonomic criteria (see Table 3). Figure 4 underline strong interspecific differentiation between the studied taxa. Compared to PC1, the N. tazetta-pachybolbus-papyraceus species constitute a group clearly opposed to N. cantabricus, N. serotinus s.l. and N. elegans. The last two species N. serotinus s.l. and N. elegans show morphological affinities. This distribution is in full correlation with the chromosome numbers.
The N. tazetta-pachybolbus-papyraceus group All of the ten Algerian populations belonging to N. tazetta share the same chromosome number 2n = 20 with sometimes one or two B chromosomes. This somatic number was previously reported by Boukhenane et al. (2015) in the district of Constantine. This number is the most commonly observed in the Mediterranean region such as in Greece, Cyprus, Italy, and Southern France (Hong 1982;Garbari et al. 1988;Baldini 1990;Dominicis et al. 2002;Aquaro et al. 2007). Other chromosome numbers have been reported e.g., 2n = 14, 20, 22, 24, 28, 30 and 32 (Sharma and Sharma 1961;Brandham and Kirton 1987). The occurrence of one or two B chromosomes makes uncertain the base number (Baldini 1995;Dominicis et al. 2002;Zonneveld 2008). Indeed, most of the studies mention only the somatic chromosomal numbers (2n) without indication on the base number. Hong (1982) refer to x = 10 following the pioneering work of Fernandes (1951Fernandes ( , 1966 who had already suggested three base numbers x = 7, x = 10 and x = 11 withing genus Narcissus. While, Brandham and Kirton (1987) have assumed a tetraploid (2n = 4x = 20) and hexaploid (2n = 6x = 30) levels for N. tazetta. On the basis of an exhaustive study on genome size measured by flow cytometry, Zonneveld (2008) has also assumed x = 5 as common base number for N. tazetta, N. elegans and N. serotinus. Most of the Algerian populations of N. tazetta show karyotypes expressing roughly similar formula. However, two populations collected in the eastern part near the Tunisian border (Oued Djenane, Tabarka), are distinguished by a less asymmetric karyotype. That of Tabarka, in Tunisia, was singularized by satellites on the 9 th submetacentric chromosome pairs contrary to those observed on the 6 th and 7 th subtelocentric chromosome pairs for some tazetta taxonomic units (Maugini1953; Hong 1982;Dominicis et al. 2002;Boukhenane et al. 2015). Due to their morphological similarities, Maire (1959) had considered N. pachybolbus and N. papyraceus as subspecies of N. tazetta. Although N. papyraceus has never been reported in the ancient flora of Algeria (Munby 1847;Trabut 1895, 1902). N. pachybolbus first described in NW of Algeria by Durieu (1846), is currently considered as an Ibero-Mauritanian species quoted in Morocco (Fennane et al. 2014) and Spain (Aedo 2010). For the Algerian populations of N. pachybolbus we have counted a diploid number of 2n = 2x = 22 consistent with previous studies (Maugini 1953;Brandham and Kirton 1987). However, in Flora Iberica, Aedo (2013) mentions 2n = 36. These two different chromosome numbers in two distinct territories suggest the need for a revision of this taxon. In our knowledge, the karyotypic formula is here provided for the first time: 6m (2sat) + 6sm (2sat) + 8st + 2t. A few karyological studies were devoted to this species. Brandham and Kirton (1987) have described just talk about a karyotype significantly different consisting of "…8 large acrocentric and 14 smaller acrocentric or submetacentric chromosomes". Our samples of N. papyraceus exhibit also 2n = 22 chromosomes confirming previous reports (D 'Amato 2004;Aedo 2013;Samaropoulou et al. 2013;Marques et al. 2017). The structure of the karyotype of N. papyraceus has been widely discussed by Brandham andKirton (1987) andD'Amato (2004). Satellites have been observed on the 6 th and 7 th chromosomes pairs in contrast to Algerian samples which exhibit satellites on the 3 rd pair only. Although the karyotypic structures of these two species were considered as similar by Brandham and Kirton (1987), the Algerian samples of N. pachybolbus and N. papyraceus differ notably in the asymmetry indices. Contrary to the karyological diversity observed between N. pachybolbus and N. papyraceus, trees resulting from molecular phylogenies reconstruction show a polytomy indicating a very close relationship between these two species (Santos-Gally et al. 2012;Marques et al. 2017).
Morphologically N. tazetta, N. pachybolbus and N. papyraceus constitute three distinct clusters (Fig. 4). In respect to PC2,N. pachybolbus and N. papyraceus (2n = 22) are clearly in opposition to N. tazetta (2n = 20). The main morphological characters involved in this differentiation, relate to the color of the corona, the size and color of the outer layers of the bulb as well as the number of flowers per scape. Although sharing the same chromosome number 2n = 22, N. pachybolbus differs from N. papyraceus by higher values in the size of the bulb, the number of flowers per scape and emerging stamens from the corona (Fig. 1, Table 2). N. papyraceus is in intermediate position between N. pachybolbus and N. tazetta. The latter shows a high morphological variability expressed by small to medium bulb with rather brown outer tunics, a perianth white to yellow and a corona lemon to orange. These results agree with molecular phylogenies (Santos-Gally et al. 2012). The specific statute of N. pachybolbus and N. papyraceus agree with recent typification and taxonomic updating on daffodils (Aedo 2010;Koopowitz et al. 2017).

Narcissus elegans, N. serotinus and N. obsoletus
Narcissus elegans and N. serotinus s.l. have been described in all ancient floras of Algeria (Desfontaines 1798; Munby 1847; Trabut 1895, 1902;Maire 1959;Quézel and Santa 1962) and several intermediate forms and putative hybrids have been reported. In Zonneveld (2008) and Marques et al. (2017), these two taxa were placed in section Serotini and section Tazettae, respectively. Some authors have grouped them together in the section Tazetteae (Santos-Gally et al. 2012). Regarding the Algerian material, these two species show close morphological relationships (Fig. 5). N. serotinus sensu lato within the meaning of Maire (1959) and Quézel and Santa (1962), is distinguished from N. elegans by its hysteranthous and smaller habit, and by "stable" characters such as single, or rarely 2, flowers per scape, larger and obtuse outer tepals. The other diagnostic descriptors, in particular the color and the shape of the corona, are variable and therefore difficult to use in practice. The inconstancy of these characters was noted by Maire (1959) and Quézel and Santa (1962) Table 3 for abbreviations). The distribution on PC1 and PC2 underlines the grouping of individuals belonging to N. tazetta, N. pachybolbus and N. papyraceus in opposition to N. serotinus sensu lato, N. elegans and N. cantabricus. The main discriminating criteria are relative to the length of the scape (Scl) and size of the bulb (Bl, Bw) as well as the number of flowers per inflorescence (Nf ) and especially the height (Ch) and color of the corona (Corcol). This analysis highlights the strong relationships between the serotinus sensu lato type with the elegans type, likewise for N. papyraceus and N. pachybolbus. grams of N. elegans show groupings preferentially in pairs of homologous suggesting a diploid level with x = 10. This is inconsistent with Donnison-Morgan et al. (2005), Zonneveld (2008) and Marques et al. (2012) who have assumed that N. elegans is tetraploid with x = 5. The karyotypic structure of N. elegans compared to that of N. tazetta from Algeria, shows similarities in agreement with the first assumptions of Fernandes (1966). The values of THL and the asymmetry indices of these two species vary within the same interval, except for CV CI and CV CL which are different. These differences would be due to chromosome structural changes as suggested by D'Amato (2004).
The Algerian populations belonging to N. serotinus sensu lato, display three somatic chromosome numbers 2n = 20, 2n = 28 and 2n = 30. The karyotype formula and the ideograms let suppose a base number x = 5 and consequently tetraploid and hexaploid levels. The tetraploids (2n = 20) were encountered in Sicily (Garbari et al. 1973) and in Greece (Phitos et Kamari, 1974), the hexaploids (2n = 30) were quoted in Italy (D'Amato 2004;Troia et al. 2013). Diploid forms 2n = 2x = 10 were mentioned in Iberian Peninsula and Morocco by Fernandes (1968Fernandes ( , 1975, Brandham and Kirton (1987) and Aedo (2013). This diploid cytotype (2n = 10) is considered very rare and would represent the N. serotinus type narrowly distributed in this region (Zonneveld 2008). In the literature, the most accepted and widespread ploidy level for N. serotinus remains the tetraploid 2n = 20. The hexaploid would raise controversy over its systematic statute. Analysis of genome size by flow cytometry led Zonneveld (2008) to attribute the hexaploid cytotype to N. miniatus which would be also confused with N. serotinus. Subsequent studies (Díaz Lifante et al. 2009;Marques et al. 2010Marques et al. , 2012Marques et al. , 2017 support that N. miniatus is an allohexaploid from N. serotinus (2n = 10) × N. elegans (2n = 20). This hexaploid form, firstly located in Spain, have a geographic range through the northern Mediterranean edge from Italy toward Lebanon, Palestine until Syria (Zonneveld 2008). On the contrary, the hexaploid specimens found by Troia et al. (2013) in Mazara del vallo (Sicily, Italy) have been attributed to N. obsoletus, which would have a larger geographic distribution area, especially in North Africa. Díaz Lifante et al. (2009) confirmed that the hexaploid cytotype of Spain and Greece belong to N. obsoletus. In our study, the karyologically examined populations are all mixed and would include individuals belonging to N. serotinus and N. obsoletus. The PCA focused on specimens of N. serotinus sensu lato and N. elegans (Fig. 5) show that the cytotypes with 30 and 28 chromosomes are all distributed along PC2. This distribution is determined by the color of the corona. All individuals located in positive pole of PC2, have orange corona and would correspond to N. obsoletus. At the opposite, individuals with yellow corona correspond to N. serotinus. This differentiation is consistent with the observations of Díaz Lifante and Andrès Camacho (2007) and Koopowitz (2017). In Algeria, N. obsoletus was often misidentified and sometimes confused with N. serotinus. In our opinion, the two species N. serotinus (4x, 6x) and N. obsoletus (6x) are well present in Algeria in mixed populations. The hexaploid cytotypes are located mainly in the center region near Algiers (Ain Tagourait, Sainte Salsa). The unusual cytotypes 2n = 28 were encountered in the northwest near Oran (Boutlélis) and Tlemcen (Ain Ftouh), could be due to aneuploidy event (Figs 4, 5). The tetraploid cytotypes (2n = 20) belongs to N. serotinus are rare in Algeria and its encountered rather in pure populations, localized mostly in the eastern region. In the IUCN Red List of Threatened Species, N. serotinus was considered uncertain in our country (Juan Vicedo et al. 2018).

Narcissus cantabricus
The presence of N. cantabricus in Algeria, was subject to controversy with N. bulbocodium. N. cantabricus was not mentioned previously in the floras of North Africa. Maire (1959) had described this species under N. bulbocodium subsp. monophyllus var. typicus with Corbularia monophylla as synonym. C. monophyla was initially reported in Algeria by Battandier and Trabut (1895) and then considered as synonym of N. monophyllus before being accepted by Quézel and Santa (1962) under N. cantabricus. N. cantabricus is distinguished from N. bulbocodium by a "white or slightly yellowish flower" (Battandier and Trabut 1895). These two species are mentioned in Flora Iberica (Aedo 2013) and Flore Pratique du Maroc (Fennane et al. 2014). Phylogenetic analyzes carried out successively by Fonseca et al. (2016) and Marques et al. (2017) confirmed their separation. The Algerian populations of N. cantabricus is diploid (2n = 14) with sometimes one B chromosome. The karyotype established here for the first time for this species, is rather symmetrical comprising mostly meta and submetacentric chromosomes. In the literature, diploid cytotypes were reported on the Cantabrian Figure 5. Principal components analysis focused on populations of Narcissus elegans and N. serotinus sensu lato A scatter plot on the first two PC of individuals of each taxon B loading of the morphological variables on the circle of correlations (see Table 3 for abbreviations). Morphologically N. elegans is well separated from N. serotinus sensu lato, by its synanthous habit (Syn), the number of flowers per scape (Nf ), a full section of the scape (SSfill). With respect to PC2, individuals of N. serotinus s.l. are distributed in two opposed groups by the color of the corona. In the negative side individuals with yellow corona (Corcol6) correspond to N. serotinus type. Others individuals with orange corona (Corcol5) belong to N.obsoletus type. N. serotinus s.l.: black circle -St Salsa, white circle -Ahfir, white triangle -Ain Ftouh, gray circle -Boutlélis. N. elegans: gray star -Boutlélis, white square -Ain Tagourait, black triangle -Santa Cruz, black square -Chenoua, black star -St Salsa.
Mounts in the north, and in the center of Spain, while tetraploids are quite rare and found in Morocco on the Anti-Atlas (Zonneveld, 2008). Therefore, the Algerian diploids would be the southernmost within the geographic range of this species. Although the haploid amount of DNA is similar in the two species, it seems that N. cantabricus derived from N. bulbocodium following structural changes (Zonneveld, 2008). N. bulbocodium is distinguished by a high polyploid series from 2x to 8x with 2n = 72 as the highest chromosome number (Fernandes 1963;Fernandes and Franca 1974;Brandham and Kirton 1987;Marques et al. 2017). N. bulbocodium is an Ibero-Mauritanian whose polyploids propagate from North to South towards Morocco and from West to East through the Maghreb as already hypothesized by Fernandes (1951). This geographical distribution of the polyploidy is similar for the two species, and therefore the Algerian diploids of N. cantabricus constitute original and interesting material. The supernumerary chromosomes in the Algerian peripheral diploids, would express an adaptive response to aridity.

Conclusion
Overall, this work has contributed with new information supplementing our knowledge on chromosome numbers, karyotypes and ploidy levels of species of the genus Narcissus. The relationships between karyological and morphological characteristics made it possible to confirm and/or update the nomenclature and the taxonomy of species of genus Narcissus in Algeria. Therefore, seven main taxa have been recognized. Into the section Tazetteae, N. tazetta and N. elegans are diploids showing 2n = 2x = 20, while N. pachybolbus and N. papyraceus have 2n = 2x = 22 chromosomes. Section Serotini is represented by both tetraploid and hexaploid N. serotinus (2n = 20, 2n = 30) and also by the hexaploid N. obsoletus (2n = 30). These two species are very similar morphologically and have long been confused with each other in the field. Among N. serotinus type, tetraploids are rare comparatively to hexaploids. The distribution of N. obsoletus (6x) is widespread from west to east through various habitats. N. cantabricus show 2n = 2x = 14 and one recurrent B chromosome and constitute the southernmost diploids, providing new element for our understanding of the distribution of polyploidy within this species.