Mediterranean plant karyological data – 33

For the first time, the chromosome number was determined for 5 species of the genus Pyrus L. ( Rosaceae ) from Armenia, viz. P. daralaghezii , P. hyrcana var. yeghegisi , P. medvedevii , P. oxiprion , P. takhtadzhianii , and the previous count of chromosome number for P. caucasica was confirmed. All the explored species have a diploid chromosome number 2 n = 34 with the basic chromosome number x = 17.


Introduction
Pyrus belongs to subtribe Pyrinae (formerly subfamily Maloideae) of family Rosaceae (Campbell & al. 2007).The area of the genus Pyrus occupies the territories from the Atlas Mountains in Northern Africa and South of France and through the whole Eurasian continent, including the Japanese seashore, and in the north from the Baltic to India in the south (Fedorov 1954; Browicz 1993).According to paleontological evidence, Pyrus probably originated in Tertiary in the mountainous regions of China (Rubtsov 1944).Centers of Pyrus diversity are in the mountain regions of East and South-West Asia, the Mediterranean and the Caucasus (Fedorov 1954; Browicz 1993).The number of the genus Pyrus species differs from 20-40 (Browicz 1993) to 80 (Phipps & al. 1990).Currently, the genus is subdivided into four sections: Pyrus, Xeropyrenia Fed., Argyromalon Fed., Pashia Koehne (Koehne 1890; Fedorov 1954).
The territory of Armenia is a center of high diversity and local narrow endemism of the genus Pyrus.About 32-34 species of Pyrus grow in Armenia, 18 of which are endemics to Southern Transcaucasia and Armenia (Akopian 2007(Akopian , 2021(Akopian , 2022)).In all of the pear habitats, especially in arid woodlands of the southern and south-eastern regions of the country, rich diversity of species and intraspecific hybrid forms of pears are observed (Akopian 2022).
Until now, the Armenian species of the genus Pyrus remain insufficiently studied in cytologenetical terms.According to the literature, only one publication is known in which was determined chromosome number (2n = 34) for 7 pear species of the Armenian flora, viz.P. caucasica Fed., P. communis L., P. complexa Rubtzov, P. fedorovii Kuth., P. nutans Rubtzov, P. salicifolia Pall.(including var.angustifolia Kuth.and var.serratula Browicz), P. pseudosyriaca Gladkova and for hybrid forms P. pseudosyriaca × P. salicifolia and P. pseudosyriaca × P. caucasica (Gladkova & Sveshnikova 1990).Since pear polymorphism is determined not only by natural variability, but also by species hybridization and naturalization of cultivars, the study of chromosome number and karyotype in Pyrus species is of particular interest.Native population-based karyological studies of Pyrus species will provide new data on chromosome number and ploidy level of Armenian Pyrus species and hybrid forms.

Materials and methods
The research was based on the Pyrus seed material, collected in nature and from the wild pears living collection of the Yerevan Botanical Garden NAS RA (Akopian 2010).Karyological investigations were made on the mitotic metaphases of the meristematic cells from root tips of germinated seeds.The root tips were pretreated in 0.4% colchicine solution and fixed in Carnoy (3:1 alcohol and glacial acetic acid).After hydrolysis in HCl for 12 minutes, the root tips were stained in Schiff reagent and were squashed on a glass slide in 45% acetic acid.For all chromosome counts, a minimum of 10 plates were examined for each taxon.The slides were examined under light microscope AmScope Photomicroscope using an oil immersion objective (100×).Determination of chromosome number was carried out by light microscope AmScope (×40, ×100) with photo camera for photomicrography.

Results and discussion
Chromosome number was determined for 6 species of the genus Pyrus from sections Pyrus, Xeropyrenia and Argyromalon native to Armenia. .
Tree up to 7-8 m in height with spherical crown; branches without thorns.Bark greyish-brown, perennial and one-year-old branches dotted with small whitish lenticels.Leaves 6.5×3.4 cm, lustrous green, elliptic, long acuminate or attenuate at apex, cuneate at base.Fruits 2×1.8 to 2.5×2.5 cm, globose, single or by 2-3, light or bright brown with lenticels, juicy and sweet.Sepals persistent in fruit, erect, crownlike, not deciduous.In Armenia it grows in pear open woodlands, 1950-2000 m a.s.l.Local endemic to Vayots Dzor province of Armenia.
In the studied specimens of P. hyrcana var.yeghegisi from its locus classicus (vicinity Flora Mediterranea 33 -2023 of village Vardahovit, Vayots Dzor province) a characteristic diploid cytotype 2n = 34 was identified, the chromosome number is given for the first time.
Tree 10-20 m in height, thorny.Leaves arachnoid-hairy along the edges and below, sometimes almost glabrous, broadly elliptical or ovate, 3-6×2-4 cm, pointed or obtuse at the apex, entire, blackening in drying.Fruits are round or slightly oblate, 2.5-3 cm in diameter, have a varied taste.
It is highly polymorphic species considered to be the ancestor of several native pear cultivars.In Armenia it grows in broad-leaved forests, by river valleys, from 600 to 2200 m a.s.l.The species was described from Armenia.General distribution: Caucasus, Northern and South-Western Anatolia.
In the karyologically studied samples of P. caucasica, a characteristic diploid cytotype 2n = 34, with a base number x = 17, was revealed.Previously, a diploid cytotype was also reported for this species from Armenia (near Dilijan, Tavush province) and from Dagestan (Gladkova & Sveshnikova 1990).Tree 5 m in height with a pyramidal crown.Leaves at the base broadly cuneate-shaped, at the apex shortly acuminated, elliptical, 8-10×3-5 cm, equally narrowed to both ends, finely sharp-dentate, ciliated, above glabrous, from beneath with scattered hairs, dry in blackening.Fruits are pear-form, fruit-stalk thick, up to 3-4 cm long.It grows in broadleaved forests, 1700-2200 m a.s.l.Endemic to Armenia.

Pyrus
In karyologically studied specimens of this species from its locus classicus (Kechut forest, Vayots Dzor province) a characteristic diploid cytotype 2n = 34 was revealed (Fig. 2).The chromosome number is given for the first time.
Tree up to 5 m in height, with dense canopy, thorny.Leaves bright green, lustrous, usually glabrous, on the margins unequally acute-serrate, narrow-oblanceolate, with the utmost width higher the middle, 3.0-7.0×1.0-1.5 cm.Fruits pear-shaped, green, very hard, ripen late.It is very ornamental with glossy green leaves, and numerous whitish-rose flowers.In Armenia it grows in arid light forests, from 1.400 up to 1.900 m a.s.l.
The species was described from North-Eastern Anatolia.General distribution: Southern Transcaucasia, North-Eastern Anatolia, Northern Iran.
In karyologically studied specimens of this species the characteristic diploid cytotype 2n = 34 was revealed.The chromosome number is given for the first time.
In karyologically studied specimens of this species, collected from the Vayots Dzor province of Armenia, a characteristic diploid cytotype 2n = 34 was revealed.The chromosome number was given for the first time.Thornless tree 5-7 m in height.The leaves are serrate or small-toothed, sometimes entire, obovate, ovate, rhombic, or narrowly elliptical, on one branch of various shapes, 4-7×2-4 cm.It has large, pear-shaped, brown, juicy fruits.According to Fedorov (1954) the Flora Mediterranea 33 -2023 303 species may have originated from ancient local pear cultivars.P. takhtadzhianii is ornamental with a crown of grayish leaves of various shapes.In Armenia it grows in broadleaved and arid light forests, among mountainous xerophytic vegetation, from 800 up to 2.200 m a.s.l.The species was described from Armenia.Endemic to Transcaucasia.

Pyrus. takhtadzhianii
In karyologically studied specimens of Pyrus takhtadzhianii from Vayots Dzor province of Armenia we revealed a characteristic diploid cytotype 2n = 34 (Fig. 3).The chromosome number was given for the first time.
It is interesting to note that the morphological variability and hybridization processes characteristic of pear species are not accompanied by the process of polyploidization.According to Gladkova & Sveshnikova (1990) polyploidy in the genus Pyrus is found mainly in cultivated species.As noted by Zelinski & Thompson (1967), speciation within the genus Pyrus occurred without changing the chromosome number, apparently the Pomoideae group arose as an allopolyploid between two primary forms having basic numbers of 8 and 9. Hieracium hypochoeroides subsp.serinense (Zahn) Greuter is a chasmophytic hawkweed endemic to Mt. Sirino (Basilicata) (Di Gristina & al. 2016a).The collective species H. hypochoeroides s. l. includes many apomictic microtaxa which have evolved probably during the postglacial period (Di Gristina & al. 2015a).In southern Europe, many of the taxa described seem to be relict (Gottschlich & al. 2017) and they are punctual endemics (Di Gristina & al. 2015b).

Introduction
In the context of updating the PhytoKaryon database (Kamari & al. 2017-onwards), which aims to record the chromosomal diversity of the plants of Greece, populations of eight native taxa were studied.Chromosome numbers and karyotypes are provided along with microphotographs of metaphase plates and karyotype morphology, while polyploidy in some of them is discussed.

Flora Mediterranea 33 -2023
The triploid chromosome number found here has already been given from another population of Chios island (Tzanoudakis 1986).The karyotype is symmetrical, consisting of metacentric and submetacentric chromosomes, ranging in size from 13.27 to 8.00 μm.The karyotype formula is given as: 2n = 4x = 12m + 9sm = 21 chromosomes.
Allium subhirsutum is a widely distributed Mediterranean species.In Greece it grows all over the country except North Pindos (NPi).
The karyotype of the population originated from Falassarna (Kriti) is symmetrical consisting of 2n = 2x = 10m + 4sm = 14 chromosomes.The size of the chromosome varies between 13.73 and 8.33 μm.

Gr
The diploid chromosome number of 2n = 2x = 8 reported here has been previously reported by several authors (Feinbrun, 1938-1940; Constantinidis & al. 1997; Bareka & al. 2008, 2012).Moreover, a tetraploid karyotype with 2n = 4x = 16 chromosomes from material originated from NE Peloponnisos on serpentine substrate has been reported (Bareka & al. 2008(Bareka & al. , 2012)).In the population studied here 2-4 satellited chromosomes are observed, while up to 6 satellited chromosomes have been reported for the species (Bareka 2008).It should be noted that satellites in the genus species are small, spherical and not always visible.The karyotype of the population studied here consists of 2n = 2x = 2m-SAT + 2st + 2sm-SAT + 2sm = 8 chromosomes ranging in size from 12.00 to 6.13 μm.The diploid chromosome number (2n = 2x = 8) and the karyotype morphology found here from Lesvos and Chios islands, are previously given from Greece and other countries (see Bareka & al. 2008Bareka & al. , 2012 for references) for references).All populations studied have a diploid chromosome number with a karyotype formula consisting of two long metacentric chromosomes with small spherical satellites on their shorter arm, two acrocentric and four submetacentric chromosomes, where one pair of them bears satellites on their long arm (2n = 2x = 2m-SAT + 2st + 2sm-SAT + 2sm = 8).Chromosome size varies from 12.33 to 6.00 μm.

Gr
The population studied here from Lefkada Island is also decaploid with a symmetric karyotype of 2n = 10x = 100 metacentric and submetacentric chromosomes.The chromosome size ranges from 3.10 to 0.85 μm.Muscari comosum occurs from Middle East Asia to the Iberian Peninsula and Canary Islands and from central Germany and S Russia to N Africa (Bentzer 1973).
A Greek endemic species, with a wide distribution on Kriti island and Gavdopoula islet, found in sandy and rocky places, scrub and mountain dolines, mainly on limestone at an altitude of 0-2200 m.
The tetraploid chromosome number of 2n = 4x = 36 found in the population studied here, has already been given by Montmollin (1986) from different localities.A microphotograph is given revealing an asymmetrical karyotype consisting of 8 long acrocentric chromosomes, 4 submetacentric and 28 small metacentric to submetacentric chromosomes.The karyotype formula is given as 2n = 8t + 4sm + 24m = 36, while chromosome size varies from 8.01 to 1.81 μm.

Introduction
Within the context of various ongoing projects in alpine systems' plants, with a particular focus on the Pyrenees, acquiring information about chromosome numbers and ploidy levels is crucial.These data are indispensable for comprehending the processes that impact the species constituting the flora in these regions.
The objective of this study is to augment existing cytogenetic datasets by providing additional information about chromosome numbers and ploidy levels of these species, in one of them (Hieracium hastile) for the first time.All plants studied have been collected in the Catalan Pyrenees (Iberian Peninsula).The information provided about their general distribution area has been obtained in all cases from Plants of the World Online (POWO, https://powo.science.kew.org,accessed November 24, 2023).This species is native to Europe, Siberia, Arabian Peninsula and NW of Africa, and introduced into Australia, America and South of Africa.
It is a ruderal species that grows on the edges of forests in the Pyrenees (Bolòs & al. 2005).
This species is a perennial plant native to NE Pyrenees & E. Central Spain (POWO).
To our knowledge, the chromosome number established in this study is the first count for this species.It agrees with counts in other triploid species of the Hieracium gr.laniferum according to Flora iberica (Mateo & al. 2017), such as H. spatulathum Scheele (Castro & al. 2007).

Hs
The tetraploid chromosome number established in this study agrees with previous counts: Favarger & Küpfer (1968) indicated n = 20 for a Pyrenean population geographically very close to the one here reported.
Native to Europe to SW Siberia and Xinjiang and N Africa to Somalia, and introduced into Australia, America and South of Africa.It grows often in ruderal locations.
The chromosome number established in this study agrees with n = 9 and 2n = 18 counts reported by Mejías (1993) from a low-altitude population located at ca. 150 km from the one here studied, and from 2n = 18 recorded from an also non-far Southern French population (Garcia & al. 2013).The same 2n = 18 number is recorded from many other provenances (Index to plant chromosome numbers, http://legacy.tropicos.org/NameSearch.aspx?projectid=9, accessed November 25, 2023).
The chromosome number established in this study agrees with the previous counts (e.g.Rotreklová & al. 2005).This is the first count in the Pyrenean area studied (https://sites.google.com/view/cromocat/home,accessed November 25, 2023).
This species is native to Europe and Northern Africa.In the Pyrenees, it grows in meadows, grazing lands and mountain trail edges.
The chromosome number established in this study agrees with the previous counts of n = 4 (Luque & al. 1984) and 2n = 8 (Izusquiza 1989) in low-altitude areas not far from the studied one, as well as in other places (e.g. in Morocco, Serra & al. 2001; in Italy, Barghi & al. 1988).This species is native to Bulgaria, France and Spain.It grows in alpine meadows.Bolòs & al. (2005) included this taxon in Taraxacum dissectum (Ledeb.)Ledeb., whereas Galán de Mera (2017) disagrees with this structuration and considers both taxa separated, with only T. pyrenaicum present in the Iberian Peninsula.

Taraxacum pyrenaicum
The chromosome number here reported confirms the count published (under the name of T. dissectum) of a population extremely close to the present one (Garcia & al. 2013).It is also consistent with the number n = 8 observed by Küpfer (1969a, b) in a population under the name of T. aff.pyrenaicum (Col du Puymorens), not far from the present one, and with the number reported by Macháčková & al. (2022) for the Encamp population in Andorra, also in the same area.The report of a triploid lineage, with 2n = 3x = 24, in the Ordesa valley (Záveský & al. 2005) is remarkable, with the taxon recorded as Taraxacum pyrenaicum group.These chromosome numbers in Eastern Pyrenees' populations differ from 2n = 32 reported for T. dissectum from China (Zhai & al. 1997).Rouy (syn.: Tragopogon pratensis subsp.lamottei (Rouy) O. Bolòs & Vigo).-2n = 2x = 12 (Fig. 1H).
The native range of this species is limited to France and Spain.This species grows in the Pyrenean meadows.
The chromosome number here reported is coincidental with the one published by Díaz de la Guardia & Blanca (1988) for a Southern Iberian population.Garcia & al. (2013) Flora Mediterranea 33 -2023 323 reported the same chromosome number for a T. pratensis -without subspecific assignationpopulation located not far from and at a similar altitude than the one studied in the present paper.In any case, 2n = 12 is constant as chromosome number for all T. pratensis subspecies with such data available (Index to plant chromosome numbers, http://legacy.tropicos.org/NameSearch.aspx?projectid=9, accessed November 25, 2023).