Iris ferdowsii Joharchi & Memariani, 2017

Memariani, Farshid & Joharchi, Mohammad Reza, 2017, Iris ferdowsii (Iridaceae), a new species of section Regelia from northeast of Iran, Phytotaxa 291 (3), pp. 192-200 : 193-196

Iris ferdowsii Joharchi & Memariani , sp. nov. ( Figs. 1–2 , 4D ).

Type:— IRAN. Razavi Khorassan: N Mashhad, south of Sandoq-Shekan pass, Gol-Khow , 1783 m, 5 May 2014, Joharchi 45170 (holotype FUMH!; isotype W!) .

Herbaceous perennial, (8–)10–20(–25) cm high, forming small dense tufts. Rhizome short, horizontally creeping with fibrous remains of leaf sheaths. Leaves (4–)5(–6), basal, ± falcate, 6–10(–20) × 0.3–0.6(–0.8) cm, green to greyishgreen, glabrous. Stem (3–)5–10(–15) cm high, erect, 1-flowered. Spathe with 2 valves, 4.5–5.5(–7) cm long, acuminate, green suffused with purple, membranous-chartaceous, with narrow hyaline margin, glabrous. Perigone tube 2.5–3.5 cm. Falls 4–5 cm long, 1.7–2.2 cm wide, elliptic-oblong, sharply reflexed, cream-coloured, heavily veined purple with a large dark-purple blotch in the upper half, bearing a dense central beard of many long white and yellowish-tipped hairs reaching from base to the middle. Standards 4.5–5 cm long, 2.5–3 cm wide, obovate to spatulate, purplish with darker veins, with a distinct narrow claw up to 1.2 cm long, bearing a central beard of hairs near the base not reaching to the middle. Anthers 1.2–1.5 cm long, whitish. Filaments 1.2 cm long, whitish, purplish at base. Styles 3.5–4 cm long, 1.3–1.5 cm wide, obovate, cream-coloured purplish-tinged, obovate, with lobes ca. 1 cm long, 0.8–0.9 cm wide. Capsules 3.5–5.5 cm long, 1.3–1.5 cm wide, provided with an apical and short (up to 2 mm long) beak. Seeds 5–6(–8) mm long, 3(–4) mm wide, ovoid, shiny brown, with rugose testa surface, topped with a distinct ring-shaped and cream-coloured aril.

Eponymy:—The specific epithet “ ferdowsii ” honours the great Persian poet “Hakim Abolghasem Ferdowsi Tousi” (940 − 1020 AD) whose tomb is located in Tous town, near Mashhad the capital city of Razavi Khorassan province, Iran. The type locality of the new species is situated 25 km NE of Pazh (Paj) village, the birthplace of him.

Phenology:—Flowering in the late April to the early June. Fruiting is completed in mid-May (in lower elevations) to mid-June (in higher elevations).

Distribution and habitat:— Iris ferdowsii occurs in medium to higher mountain steppes (1400 − 2750 m elevation) of Hezar-Masjed range in NE Iran ( Fig. 3 ). It grows on stony gentle slopes or limestone terraces. In the medium mountain steppes of the area, it occurs in different vegetation types such as sagebrush and grassy steppes with a diverse flora. In the higher mountain steppes, it inhabits mostly in thorn-cushion vegetation ( Fig. 1A ) which is mainly composed of Gypsophila aretioides Boissier (1843: 9) , Onobrychis cornuta ( Linnaeus 1763: 1060) Desvaux (1814: 81) , Acantholimon Boissier (1846: 69) , and also Eremurus stenophyllus Baker (1877 a: 281) .

Additional specimens examined (paratypes):— IRAN. Razavi Khorassan: SW Daregaz, Allah Akbar pass, 1650 m, 30 April 1988, Joharchi & Zangooei 16320 ( FUMH!) ; SW Daregaz, Allah Akbar pass, 1710 m, Foroughi 5332 ( TARI!) ; NE Mashhad, 65 km on the road towards Kalat , 1550 m, 19 June 1991, Faghihnia & Zangooei 20876 ( FUMH!) ; SE Kalat, Zharf mountains , 2100 m, 19 May 1994, Faghihnia & Zangooei 23948 ( FUMH!) ; SE Kalat, between Ortekand and Sar-Rud , 1400 m, 19 May 1994, Faghihnia & Zangooei 23973 ( FUMH!) ; N Mashhad, on the old road towards Kalat, next to Sandoq-Shekan pass, 1400-1450 m, 4 May 2007, Zangooei & Neshati 38749 ( FUMH!) ; N Mashhad, Hezar-Masjed Mountains, 15 km north of Kharkat , Qezel-Khesht Mt. , 2150 − 2450 m, 20 May 2012, Joharchi & Memariani 44785 ( FUMH!) ; NW Mashhad, 9 km from Hezar-Masjed summit towards Karim- Abad , 2750 m, 5 June 2012, Joharchi & Memariani 44858 ( FUMH!) ; N Mashhad, on the road towards Kalat, on the bifurcation road towards Khowr , 1614 m, 29 April 2015, Joharchi & Memariani 45369 ( FUMH!) (in flower) ; ibidem, Joharchi & Memariani 45370 ( FUMH!) (in fruit) ; SW Daregaz, northern slopes of Allah Akbar pass, 1700 m, 27 April 2016, Joharchi & Memariani 45722 ( FUMH!) .

Conservation status:—According to IUCN Red List Categories and Criteria( IUCN 2016), the extent of occurrence (EOO) and the area of occupancy (AOO) for the new species are estimated 1100 km 2 and 889 km 2, respectively ( Fig. 3 ). Regarding the geographic distribution range, populations are severely fragmented and a continuous decline is observed in the extent and quality of habitats. Therefore, I. ferdowsii is here assessed as Endangered [EN B1ab(iii,iv)]. The eastern and southeastern parts of the species range are not only outside of the officially protected areas, but also are intensely grazed by livestock and also degraded by agricultural over-exploitation and climate aridity. Some populations are located in the borders of Ors-e Sistan (Hezar-Masjed) and Allah Akbar Protected Areas. These protected areas were rather recently established (in 2000 and 2009, respectively), therefore the habitats have experienced a disturbance history, mainly by over-grazing and road construction. So, urgent in situ and ex situ conservation practices are needed to protect the remaining populations of the species.

Taxonomic relationships:—The species of Iris sect. Oncocyclus and I. sect. Regelia , two groups of Iris s.str. with an aril on their seeds, seem to be in an active diversification and evolution in eastern Mediterranean, through eastern Turkey, Caucasia, Iran and Afghanistan to Middle Asia. The northeastern part of Iran is the westernmost and easternmost range of distribution for the species of both sections, respectively.This area belongs to the Khorassan-Kopet Dagh (KK) floristic province of the Irano-Turanian region, which is well-known for holding a unique combination of flora and diverse vegetation types, as well as 14% of plant endemism ( Memariani et al. 2016a, 2016b) which is above the average in the neighbouring Central Asia ( Sennikov 2016). On the one hand, the northeastern corner of Iran was hitherto known as the westernmost extreme of the range of sect. Regelia ; however, the discovery of I. ferdowsii extends the range of this section further westwards to the Eastern KK in Hezar-Masjed mountain range and partly to the Central KK in Allah Akbar mount ( Fig. 3 ). Central and Eastern KK are the main areas of that floristic province with a high endemic distinctiveness ( Memariani et al. 2016b). On the other hand, I. acutiloba is the only species of I. sect. Oncocyclus whose distribution range extends to the Western KK (North Khorassan province, and S Turkmenistan). So, the ranges of both sections come close together in KK, though they do not overlap based on the current data. In the area, I. acutiloba subsp. lineolata ( Trautvetter 1870: 24) Mathew & Wendelbo (in Wendebo & Mathew 1975: 32) grows on flat plains or lower to medium elevation mountain belt in Western KK, where the habitats receive higher annual precipitation than that of Central-Eastern KK which covers the distribution range of the new species I. ferdowsii . Morphologically, Iris ferdowsii can be distinguished easily from the species of I. sect. Oncocyclus by its bearded standards, despite of having 1-flowered stem. In pressed and dried herbarium material, the colour of perigone segments of I. ferdowsii and I. acutiloba ( Fig. 4 ) changes to purplish, so they may be confused if the diagnostic characters such as the bearded standards and the shape of floral segments are not checked carefully. For this reason, it seems that Mazhari (2000) overlooked the new species from Central-Eastern KK specimens (such as 5332 -TARI!; and also 16320, 20876, 23948, 23973 -FUMH! on sheet labels), which she identified as I. acutiloba subsp. lineolata . Furthermore, I. ferdowsii differs from the other species of I. sect. Regelia in the Flora Iranica area by several morphological characters ( Table 1). It can also be distinguished from I. falcifolia by its longer and wider perigone segments (falls and standards) and styles and also by the shape of floral parts ( Fig. 4 ). Iris falcifolia actually resembles I. sect. Regelia , however, it has been classified within I. sect. Hexapogon Bunge (1852: 329). Moreover, I. kuschkensis Grey-Wilson & Mathew in Grey-Wilson (1974: 67), an endemic species to NW Afghanistan with a close geographical range to the new species, can be distinguished by its higher stature, 2-flowered stem and more or less straight leaves among other characters.

Figures

FIGURE 1. Iris ferdowsii in natural habitat. A) Habit; B–C) Close-up view of floral parts.

FIGURE 2. Iris ferdowsii. A) Plants in fruiting stage; B) The short horizontally creeping rhizome; C) Flower segments, left to right: standard, fall, stamen, and style (scale bar = 1 cm); D) Seed with an aril on the top (scale bar = 1 mm).

FIGURE 3. GeoCAT distribution map of Iris ferdowsii in Hezar-Masjed Mountains, NE Iran, and estimation of Extent of Occurrence (EOO = 1100 km2) and Area of Occupancy (AOO = 889 km2), with maximum distance of 130 km between pairs of points, based on IUCN Red List Criteria.

FIGURE 4. Bearded irises (Iris s.str.) in NE Iran. A–B) I. falcifolia (I. sect. Hexapogon) with bearded hairs on falls (A) and also on standards (B). C) I. acutiloba subsp. lineolata (I. sect. Oncocyclus). D) I. ferdowsii (sect. Regelia), showing bearded hairs on standards.