Linum khorassanicum Joharchi & Behroozian, 2017

Behroozian, Maryam, Vaezi, Jamil, Joharchi, Mohammad Reza & Memariani, Farshid, 2017, A new species of Linum (Linaceae) from Iran with a focus on description of Linum turcomanicum in view of morphological and molecular analyses, Phytotaxa 299 (2), pp. 151-168 : 161-164

Linum khorassanicum Joharchi & Behroozian , sp. nov. ( Fig. 4 )

Type: — IRAN. North Khorassan: W Bojnurd, Ghorkhod Protected Area , 7 km west of Zard towards Kastan , 1510 m, N 37º 30 56.5˝, E 56º 29 02.0˝, 23 May 2013, Joharchi, Memariani & Behroozian 45035 (Holotype: FUMH, Isotype: TARI) ; Paratypes: ibid. 45036, 45037 ( FUMH) .

Perennial. Roots thick and robust, becoming woody. Flower-bearing stems few, 22–35 cm high, erect, otherwise nearly prostrate or decumbent at base, thick, rigid, cylindrical, pale green; sterile stems with short, many and nearby imbricate leaves, unbranched or branched at apex. Leaves 3–12 × 0.7–1.5(2) mm, erect, linear, nerveless or 1-nerved, usually involute at margins, acute, green. Inflorescence 1–3-flowered; pedicels erect, straight, thick, short in flowering, 9–20 mm long in fruiting. Flowers 36–48 mm in diameter. Sepals rather large, three outer sepals 6.5–8 × 3–5 mm, ovate, acute to round at apex, narrowly white- membranous at margin, two inner sepals broadly ovate, rounded at apex, broadly white-membranous at margin, 0.9–1.5 mm wide, 3–5-nerved, hardly protruding below, median nerve extended to apex, pale green. Petals 18–24 × 12–15 mm, broadly obovate, rounded at apex, blue, gradually tapering below to yellowish claw. Stamens only in long-styled forms, 7.5–8 mm long; anthers 3–3.2 mm long. Styles filiform. Stigma capitate. Capsules 10–11 × 9 mm, broadly ovoid, tapering at apex and acuminate, becoming cream-brown; septa ciliate. Seeds 5–5.5 × 2.5–2.7 mm, flattened, obliquely ovate- elliptic, shiny brown. May–July.

Additional specimens examined: — IRAN. W Bojnurd, Ghorkhod Protected Area, 2 km on the bifurcation road towards Ternuli valley, on the hills of silviculture plan, 1540-1600 m, N 37º 23 28.1˝, E 56º 26 27.4˝, 18 May 2010,

Memariani & Arjmandi 43677b ( FUMH); W Bojnurd, Ghorkhod Protected Area, northern slopes of Ghorkhod Mt., 2000-2700 m, 18 July 2003, Assadi & Hamdi 85589 ( TARI); W Bojnurd, Ghorkhod Protected Area, Ghorkhod Mt., 1600 m, 17 July 2003, Assadi & Hamdi 85489 ( TARI); Northeastern part of Golestan National Park, ca. 7 km west of Soolgerd, in open Juniperus wooldland and Artemisia steppe, 1300- 1600 m, N 37º 27’, E 56º 4’, 28 April 1995, Akhani 10541 (Hb. Akhani); Northern part of Golestan National Park, near Koilar, on gypsum marl, 1131 m, N 37˚ 31’ 14”, E 55˚ 58’ 47”, 23 June 2003, Akhani 16864 (Hb. Akhani). For the other specimens refer to table 1.

Etymology: —The specific epithet refers to the distribution range of the new species in North Khorassan province in the northeast of Iran.

Distribution, habitats and conservation: —So far, L. khorassanicum has been found in the middle mountain steppes of Aladagh range, Ghorkhod Mount and adjacent north-eastern parts of Golestan National Park in North Khorassan Province ( Fig. 1 ). It usually grows on north, northwest and west facing slopes, between 1100–2500 m a.s.l. Based on a phytosociological relevé in the type locality in Mt. Ghorkhod and observations of the habitats in northern slopes of Aladagh range, the new species grows in grassy mountain steppes dominated by Festuca valesiaca Schleicher ex Gaudin (1811: 242) community with a dense vegetation coverage of nearly up to 100%. The habitats are usually very rich in annuals and herbal perennials with scattered woody species ( Table 4). The specimens 10541 (Hb. Akhani) and 43877 (FUMH) recorded as Linum austriacum in previous publications (Akhani 1998 and Memariani 2016c, respectively) belong to the new species L. khorassanicum . Akhani (1998) referred to the necessity of further studies on the specimen from Golestan National Park named as L. austriacum because of some morphological differences in the easternmost populations of the recorded species.

23V2013, elevation: 1510 m, gradient: 10–15°, aspect: N-NE, total cover: 90%. Cover-abundance scales are based on BraunBlanquet (1964).

Biogeographically, the new species is a narrow endemic element of western Khorassan-Kopet Dagh (KK). The Khorassan-Kopet Dagh floristic province is located in mountainous areas of northeastern Iran and partly in southern Turkmenistan. The area is a transition zone and a corridor connecting different phytogeographical units of the Irano-Turanian region with a high rate of 14% endemism in its total flora ( Memariani et al. 2016a, 2016b). According to IUCN Red List Categories and Criteria ( IUCN, 2011), L. khorassanicum is here assessed as Endangered (EN, B1+2ac (i,iii)). Its extent of occurrence (EOO) is about 400 km 2 with few and severely fragmented locations. The habitats in Aladagh range are not officially protected and the main localities in Ghorkhod Protected Area, including the type locality, are situated in poorly protected parts of the northern borders of the area recently damaged by extending the agricultural fields and road construction ( Memariani et al. 2016c). The new species is therefore considered to be facing a very high risk of extinction in the wild and needs very urgent in situ and ex situ conservation efforts.

Figures

FIGURE 1. Geographical distribution of Linum khorassanicum (squares), L. turcomanicum (triangles) and L. austriacum (circles) in the region under study. The localities are based on herbarium records and also distribution data in Flora Iranica (Rechinger 1974).

FIGURE 4. Holotype of Linum khorassanicum sp. nov. (Joharchi, Memariani & Behroozian 45035 (FUMH)).