Onosma anatolica Binzet, is described and illustrated as a new species from Niğde province in southern Anatolia, Turkey. It belongs to sect. Onosma L. subsect. Asterotricha (Boiss.) Gürke. The new species is closely related to Onosma subulifolia Riedl from which it is distinguished. O. anatolica is readily distinguished from O. subulifolia by its sterile shoots, the green-grey stem indumentum, longer bracts, yellow and puberulous petals. The IUCN threat category of O. anatolica is determined as “CR (Critically Endangered)”. A distribution map and anidentification key for O. anatolica and O. subulifolia supplement the study.

Boraginaceae , Onosma , Endemic, Niğde, Turkey

The family Boraginaceae s.s. comprise some 1600 species (Chacon et al. 2016, Luebert et al. 2016Mehrabian et al. 2012, Kolarčik 2010; Cecchi and Selvi 2009). Members of the family are widespread in western and central Asia and in the Mediterranean area (Jávorka 1906, Meusel et al. 1978). The family comprises about 44 genera and 375 species in Turkey (Güner 2012).

The genus Onosma L. (Boraginaceae-Lithospermeae) is one of the largest in the Boraginaceae and includes about 230 species, mainly distributed in the Mediterranean region, southwest Asia, and temperate Europe (Boissier 1879, Riedl 1967, Peruzzi and Passalacqua 2008, Binzet et al. 2010, Mehrabian et al. 2011, 2014, Ranjbar and Almasi 2014). In Turkey, the genus is represented by about 103 species as the rate of species endemism amount to 50% (Riedl 1978, Davis et al. 1988, Yıldırımlı 2000, Riedl et al. 2005, Binzet and Orcan 2007, Kandemir and Türkmen 2010, Aytaç and Türkmen 2011, Koyuncu et al. 2013, Guner 2012, Binzet 2016). This genus is perennial, usually suffrutescent or consists of biennial herbs (Stevanovic et al. 2003, Akçin and Binzet 2011). Onosma is systematically difficult, and most of the diagnostic characters are based mainly on the whole indumentums, leaf and flower morphology (Ball 1972, Riedl 1978, Peruzzi and Passalacqua 2008, Pavlova 2009). To identify the sectional categories of the Onosma members, the indumentum of the stem and the leaves are of significance (Özcan 2009). The genus has been divided into three groups, originally described as sections, but here recognized only as informal groups: Asterotricha, with basal leaves covered by stellate trichomes or asterosetae (i.e. along tubercled seta with several shorter rays at its base), Haplotricha, with basal leaves covered by simple setae, and Heterotricha, with both simple setae and asterosetae on the basal leaves (Boissier 1879, Peruzzi et al. 2004, Peruzzi and Passalacqua 2008, Koyuncu et al. 2013).

During a field trip in June 2011, some interesting Onosma specimens were collected from the Niğde province in Southern Anatolia. The few plants gathered in 2011 were complemented by collection conducted in June 2015 from the same site. Detailed morphological studies indicated that the population of Onosma from the Niğde province represent a hitherto unknown species related to O. subulifolia. This species is described here as new to science bringing the total number of the species known from Turkey to 104.

Specimens of Onosma anatolica were collected by the author during three field excursions in Niğde province in June 2011 and June 2015. Totally 8 herbarium specimens were collected from one locality and deposited in ANK, GAZI and the Herbarium of Mersin University. I have compared the new Onosma anatolica specimens with O. subulifolia based on relevant taxonomic literature (Riedl 1978). The holotype photo of O. subulifola was taken from E. Preliminary conservation assessments were made using the IUCN (2012) guidelines. For the palynological definision in total 50 pollen grains and 20 mature nutlets were measured using a light microscope (LM) and stereo-binocular microscope. In addition, observations were made using a scanning electron microscope (SEM).

For pollen studies using LM, grains were taken from fresh and herbarium materials prepared according to the Wodehouse methods (Wodehouse 1935). The polar axis (P), equatorial axis (E), and other characteristics (plg, plt, clg, clt, exine, intine and t; see Table 1 for abbreviations) of the pollen grains were measured using an Olympus BX40 with a 100× objective until a Gaussian curve was acquired (Table 1). For SEMobservations, pollen grains obtained from each specimen were transferred onto stubs and coated with platinum. The SEM micrographs were taken with a ZEISS supra 55. In this study, nomenclature for pollen morphology was used in accordance with Wodehouse (1935), Faegri and Iversen (1989) and Punt et al. (1994).

Morphological characters of Onosma subulifera used in this paper for comparation were obtained from relevant taxonomic literature (Riedl 1978).

Onosma anatolica belongs to Onosma sect. Asterotricha subsect. and it is distributed in Southern Anatolia (Niğde) and grows on the steppe and rocky pastures. It is an element belong to the Irano-Turanian floristic region. It shows some affinity to O. subulifolia which is placed in the same subsection and can be easily distinguished from that species by its sterile shoots; green-grey stem with adpressed setose trichomes, the setae arising from stellate hairy and shortly hairy, sterile rosette leaves and basal leaves -50 × 1–1.5(-1.8) mm; revolute-subulate, cauline leaves -20 × 1–1.5(-1.8) mm; bracts 8–15 × 1–2 mm; calyx 6–8 mm in flower, 8–12 mm in fruit, suboblate, patent strigose on ±tubercles and shortly hairy on the outside, rarely hairy on the inside; yellow corolla, clavate, puberulous, nutlets 3–3.5 × 2–2.3 mm in size, short beaked, grey. Details of the differences between O. anatolica and O. subulifolia are presented in Table 2.

I would like to thank the SEM laboratory of Mersin University (MEİTAM) for helping me with the SEM studies.