Psephellus vanensis (Asteraceae), a new species from east Turkey

Abstract A new species, Psephellus vanensis A.Duran, Behçet & B.Dogan (Asteraceae) from Anatolia, Turkey, is described and illustrated. The species grows on the serpentine stony field of the village of Çaldıran in the district of Başkale (Van province) in eastern Anatolia. It is morphologically similar to Psephellus pyrrhoblepharus (Boiss.) Wagenitz. Diagnostic characters are discussed, and a key to the most similar species is provided. Ecology, conservation status and notes on biogeography of the species are also presented. In addition, the geographical distribution of the new species and other related species in Turkey is mapped.


Introduction
Th e genus Psephellus Cass. embraces 75-80 species. Its distribution is centered in east Anatolia, the Caucasus and northwest Iran; only few species occur outside this area (Wagenitz and Hellwig 2000).
In Wagenitz and Hellwig (2000), 12 sections that had been included in the genus Centaurea were transferred to the genus Psephellus, namely P. sect. Psephelloideae (Boiss.) Wagenitz  New combinations under the genus Psephellus were provided for these sections and 35 species, especially from Turkey and Iran. Some of these species occur only in Turkey.
During a fi eld trip, some specimens of the genus Psephellus were collected in easthern Anatolia, in the Van province. After examining carefully the specimens and the descriptions of Psephellus species in Wagenitz (1975), Dostal (1976), Davis et al. (1988), Wagenitz et al. (1998), Wagenitz and Hellwig (2000), Güner (2000), Duran and Hamzaoğlu (2005), Wagenitz and Kandemir (2008), Duran et al. (2009), as well as comparing with specimens in the Herbaria KNYA, ANK, GAZI, GOET, HUB, E, K and BM, it was determined that our specimens represent a species new to science. In this paper, this new species of Psephellus is described and illustrated.
Ecology Distribution and conservation status. Psephellus vanensis is endemic to east Anatolia, where it seems to be very local. It belongs to the Irano-Turanian element (Fig.  4). Th e species is known only from type gatherings and from an area of approximately 0,006 km 2 (criterion B1). Because of overgrazing, the habitat of this species is under threat, and this situation leads to potential reduction in the number of individuals (criterion A). Th e population is in a poor condition, and the number of individuals is estimated to approximately 120-125 (criterion C2). Th erefore the species should be regarded as Critically Endangered (IUCN 2014).  Wagenitz (1975), Wagenitz and Hellwig (2000).

Key to the related
Affi nity. Psephellus vanensis is closely related to P. pyrrhoblepharus, which occurs in Central Anatolia and is endemic to Turkey. It mainly diff ers from P. pyrrhoblepharus in its stem 13-20 cm tall and densely tomentose (vs. 30-50 cm, fl occose-tomentose), basal leaves usually undivided and elliptic to lanceolate, rarely lyrate with 2-3 pairs of lateral segments (vs. lyrate with very large broadly lanceolate terminal segment and 1-2 pairs of small lateral segments).
Additional characters of P. vanensis and the related species P. gilanica and P. pyrrhoblepharus are provided in Table 1.
Phytogeography. Th e east Anatolia region is a botanically interesting area, occupying the Irano-Turanian phyto-geographical region. Th e area is very rich in local endemic plants (Akman et al. 2011;Koçyiğit and Bona 2013). Recently many articles were published on new species from this particular region, notably