Abstract
A new species of Gagea iranshahrii ***** & ***** (Liliaceae,G. sect. Stipitatae (Pascher) Davlianidze) has been described from the basin of the Atrak River basin, Iran and Turkmenistan. Morphological features and a distribution map are given. Differences from four superficially similar taxa are indicated. The new species differs in the totality of features and, especially, in the presence of a relatively large, rounded vegetative bulb, which forms annually throughout the entire ontogenesis.
Keywords : Gagea , Liliaceae, Iran, Turkmenistan, New species
1. Introduction
During an expedition to Golestan province, NE Iran, a new taxa ofGagea Salisb. was discovered in the basin of the Atrak River (also called Etrek, Atrek) on the dry foothills of the eastern part of the Alborz ridge (Figs. 1- 3). Identification of the sample with the help of modern literary sources (e.g. Wendelbo and Rechinger 1990, Zarrei et al. 2007, 2011), placed it next to G. tenera Pascher. But the habitus and according to the totality of signs, this taxon belongs to sect. Stipitatae (Pascher) Davlianidze. This finding showed the greatest similarity with G. subtilis Vved. from the Western Pamir-Alai, G. vanensis Tekşen et Erkul from Eastern Turkey (Tekşen and Erkul 2015) and G. namanganica Levichev & Karimov from the Fergana valley (Levichev et al. in pres.).
According to herbarium materials, the same plant was identified from four more points: on the slopes of Kopet Dagh and on the hills of the Big Balkhans in Turkmenistan (Fig. 3). The samples clearly differed from all the previously named and known representatives of the genus. The habitats of the new taxon are located far beyond the two centers of the modern diversity of the genus in the Western Tien Shan and in the Western Pamir-Alai, but inside the hypothetical area of its origin in the Irano-Turanian region of Near Asia (Levichev 1999b, Peterson et al. 2019).
In the lily family (Liliaceae), the genus Gagea is the largest, with more than 330 species. Its representatives are distributed in temperate and subtropical regions of Eurasia, as well as along the Mediterranean coast of Africa (Levichev 2011, 2013). The largest number of species of the genus is concentrated in Southwest and Central Asia (Rechinger 1986, Peterson et al. 2008, 2009, Peruzzi 2012). According to our calculations, more than 220 of its species are currently concentrated in region “No. 1” in Southwest Asia (see map charts: Levichev 1999b, Levichev 2008). In the same region, on the western spurs of the slopes of the Tien Shan and Pamir-Alai descending to the Turan lowland, there are both centers of modern diversity of the genus, numbering more than 80 and 110 species, respectively. This is significantly more than for any other geographically compact (and larger) territories. For example, 37 species and 3 subspecies are known for the Caucasus region (Levichev 2006, Timukhin et al. 2010), 36 species in Pakistan (Ali and Levichev 2007), 31 species along the slopes of the Himalayas (from Pakistan to Nepal). According to Flora Iranica (Wendelbo and Rechinger 1990) with subsequent additions (Zarrei and Zarre 2005; Zarrei et al. 2007, 2010, 2011; Ajani et al. 2010), 35 species are mentioned for the territory of Iran. Excluding synonyms, within these limits (according to our analysis) there are 29 species ofGagea , and considering the one described in this publication, reached up to 30.
The flora of the Golestan province, NE Iran, is very diverse. 1,302 species are known from Golestan National Park (GNP) (Akhani 1998), which is about 19% of vascular plants of Iran. In the flora of GNP, several contrasting phytogeographic regions come into contact, which create such a high floral diversity. Recently, the vegetation and flora composition of the Ghorkhod Protected Area (GPA) adjacent to the GNP in North Khorassan has been studied in depth (Memariani et al. 2016). The flora of northeastern Golestan province remains insufficiently studied and is limited to a few additions from easily accessible places (Hamdi et al. 2006, Khasanov et al. 2006, Ranjbar 2007). In addition, the recognition and taxonomy of representatives of the genus Gagea is complicated due to the insufficient amount of material from this region, and is also associated with the loss of many diagnostic features during herbarization (Rechinger 1986).
The distribution sites of new taxon are located in the northeast of Golestan province near Maraveh Tappeh. According to the meteorological station of Maraveh Tappeh, the average annual temperature and precipitation are 18.8°C and 361.5 mm, respectively. Precipitation falls mainly in winter. Based on the Köppen criteria, this climate correlates with the BWh type, that is, the climate of a hot and arid desert (Peel et al. 2007).