Iris pseudomeda Salimbahrami & Saeidi, 2021

Salimbahrami, Mona, Saeidi, Hojjatollah & Bagheri, Ali, 2021, Iris pseudomeda (Iridaceae), a new species of Iris section Oncocyclus from Iran, Phytotaxa 527 (1), pp. 75-82 : 76-79

Iris pseudomeda Salimbahrami & Saeidi , sp. nov. ( Figs. 1 –2,4A)

Type:— IRAN. Kurdistan province: Divandarreh, Zarrineh rural district, 36°05´67”N 46°54´24”E, 2140 m of elevation, 26 May 2019, Saeidi & Salimbahrami 23404 (holotype HUI!; isotypes HUI!) .

Diagnosis:— In terms of vegetative characteristics, I. pseudomeda differs from I. meda by having exactly 4 leaves not more, almost erect, vividly membranous and smooth edge versus strongly falcate and crinkled margin with inconspicuously membranous parts of the edge in I. meda . Furthermore, I. pseudomeda shows green spathe valves, swollen and acuminate (not lanceolate and purplish green), with 4–5.5 cm in length (not longer). Regarding the floral differences, excepting the smaller perigon size, the golden brownish flower of I. pseudomeda with crenate segments densely bearded by white long hairs stunningly impresses at first glance rather than the yellowish colour of I. meda with entire petals, usually yellow and nearly scattered hairs, not compacted in a bushy form ( Figs. 2–3 ). In addition, I. pseudomeda varies by its blunt elliptic falls with the wing-like extension at the middle part and spatulate standards vs. obtuse lanceolate falls and obovate standards as it is in I. meda ( Fig. 6 ). Comparing with I. barnumae , the floral differences are more obvious, excluding perigon size and its purple colour, I. barnumae differs by slender and purplish green coloured spathe valves, obovate falls and standards barely veined by rounded apex bearing yellow or dark purple diffuse hairs and unclear signal spot ( Figs. 2–3 ).

Description:— Plant herbaceous perennial, 8–15 cm high, forming small bunches sitting very close together. Rhizome short and knobby, creeping horizontally with very slender roots. Leaves 4, basal with transparent leaf sheaths, straight but nearly curved only in longer ones, 0.2–0.3 cm broad, greyish green, glabrous, with shiny hyaline and smooth margin. Stem (5–)7–9(–10) cm long, erect, 1-flowered. Spathe with 2 valves, green, swollen, 4–5.5 cm long, acuminate, glabrous, membranous at the edge and broadly membranous at the tip. Flower 3–5 cm in diameter, brownish. Perigone tube 1–3 cm long. Falls 3.5–4 cm long, 0.8–1.5 cm wide, blunt elliptic, minutely crenulate, reflexed at the inconspicuous wing-like parts, brown at the upper half and shiny yellow at lower half, heavily veined by darker brown with purple signal blotch downright above the beard (purplish patch spread on upper half and amalgamated by the ground color), bearing long white hairs in a bushy form at the middle of falls to the base. Standards 3.5–4 cm long, 0.5– 1 cm wide, oblong to spatulate with almost the same ground colour in upper and lower parts as falls, strongly veined darker brown, both crenate and undulate. Anthers 1.3–1.5 cm long, whitish. Filaments 1.3–1.5 cm long, whitish. Style branches 1.5–2 cm long, 0.8–1.5 cm wide, obovate, crenate, golden yellow intensely dotty (in a way seen as brownish inside). Stigma crenate, narrowly reflexed at the highest edges, with rounded crests and superficially bilobate. Immature capsule spindle-shaped, 2 cm.

Etymology:—The specific epithet “ pseudomeda ” refers to its morphological affinities with Iris meda , an exclusively Persian species from western Iran, to which the new species is akin, especially by the golden brilliance of its flowers.

Phenology:—Flowering from early May to the early June. Fruiting will have been completed by mid-June, as soon as the temperature rises for the first time after flowering.

Distribution: — Iris pseudomeda is considered as a locally endemic species, most probably isolated in a small population but may be found in the same elevation and climatic conditions around, in Kurdistan province. Until now, the species is only known from the type location distinctly different from other comparable species based on old addresses.

Ecology and habitat: — Iris pseudomeda grows on stony slopes and hillsides between the elevation of 2000−2200 m in the Kurdistan Province, northwest of Iran ( Fig. 4A ). Flowering and fruiting time of plants in high altitudes occur within brief vegetative seasons due to the intensively arid summers and long-term snow covering. As the latter reason provides water resources, thereby, snowmelt is a key factor determining the vegetation patterns in high mountainous areas ( Noroozi 2008). Consequently, flexible phenology of Oncocyclus in western and northwestern Iran is understandable, and that is why completely mature capsule and seed of I. pseudomeda were not available for the present study. This new species inhabits Kurdo-Zagrosian ecoregion within subalpine zone associated with Astragalus sp. pl., Prangos sp. , Poa sp. and Lactuca orientalis Boissier (1875: 819) ( Fig. 4B ).

Conservation status:— According to the IUCN Red List Categories and Criteria ( IUCN 2019), I. pseudomeda need to be addressed as a Critically Endangered species (CR, B1+2ab(iii)). It is at present restricted to a narrowly bounded population and finite locations. During our first collecting trip to the type locality, we also observed that it had been extremely grazed by a herd of farm animal in a non-protected area ( Fig. 4B ).

Taxonomic relationships: —Species of I. sect. Oncocyclus are distributed across the eastern Mediterranean, Turkey, Caucasian area and Iran, typically in minor populations ( Mathew 1989). Their geographical distribution in Iran occurs from western and northwestern region within Zagros mountain range to the north and northeastern parts on Alborz mountain range, extending to the northern Khorasan. Also, they spread through central Iranian plateau within southern Alborz and Zagros mountains to central Iranian range ( Mazhari 2000, Memariani & Joharchi 2017). Iris pseudomeda is located in the subalpine zone of Kurdo-Zagrosian steppe-forest ecoregion, in northwestern Iran ( Zohary 1973). Based on the recent biogeographical analyses of Oncocyclus , the Caucasus has been considered as an ancestral area ( Wilson et al. 2016) southerly bordering the northwestern part of Iran, and the northeastern region of Turkey ( Solomon et al. 2014). Regarding the northwesternmost distribution of I. meda area and the southernmost area of I. barnumiae f. protonyma ( Stapf 1932: t. 9279) Mathew & Wendelbo (1975: 34), they approach along the northern Kurdistan province, and it was proposed that there might be an introgression zone between these two species (Mathew & Wendelbo 1975). It has been mentioned that I. meda is characterized by variously and very wide range of coloured hairs and segments ( Mathew 1989, Mathew & Wendelbo 1975). Among the localities cited for I. meda , there are only two being very close to the type locality of I. pseudomeda . The one reported in Flora Iranica , “ Kurdistan, 3 km N Zarineh, 2160 m of elevation (E00332842,1966)” fits I. meda remarkably showing an extra pair of spathes in company with two externally falcate leaves and two internally erect leaves. The second locality indexed in Flora of Iran, “ Kurdistan, Ahmadkaar, between Sanandaj and Saghez, 2100 m of elevation, 2000” was marked by purple hairs and complex form of leaves in a similar way as the last one. Both latter specimens have been considered as an exclusive hybrid species from Iran, I. meda × I. barnumiae . The specimens regarded as hybrids were determined by at least a couple of intermediary morphological characteristics, but they pertained to either I. meda or I. barnumiae ( Fig. 5 ). In the recent decades, by employing multivariate investigations on large data sets, it has been comprehended that morphological intermediacy is an unsatisfactorily inadequate reason for tracing back of the hybrid ancestry and this sort of specimens need to be studied by cytological methods, chemical and/or molecular markers ( López-Caamal & Tovar-Sánchez 2014). From this point of view, it should be noticed that not only does I. pseudomeda have distinctly coloured and shaped hairs, but it also turns up other distinguishable characteristics from both I. meda and I. barnumiae ( Table 1 ). The newly described species is characterized by smaller size in total height and flower, brownish coloured and crenate segments, elliptic-shaped falls with inconspicuous wing-like extension and long whitish hairs spreading in a compact form ( Fig. 3–5A , 6 ). In terms of morphology, I. pseudomeda is easily defined from other Oncocyclus species, even its affiliates in natural habitats, but as a pressed herbarium material it would be more challenging to be recognized from particularly I. meda , although its vegetative (not floral) traits, comprising the number and shape of leaves beside the form of spathe valves would come to help the identification process ( Table 1 ). The most important character is that the brownish colour of I. pseudomeda flower segments turns bluish or purplish when dried, but in I. meda , it only gets dimmer yellowish.

Figures

FIGURE 1. Iris pseudomeda in nature. A–B) Habit; C–D) Detailed view of the flower and leaves.

FIGURE 2. Botanical illustration of Iris pseudomeda.

FIGURE 3. Schematic illustration of petals in Iris pseudomeda. A) Fall blunt elliptic, crenulate with the wing-like prominence at the middle (3.5−4 × 0.8−1.5 cm); B) Standard spatulate, crenate and undulate (3.5−4 × 0.5−1 cm).

FIGURE 4. Geographical distribution of I. pseudomeda in the west of Iran. A) Schematic map; B) Natural habitat.

FIGURE 5. Iris pseudomeda and close species from sect. Oncocyclus. A) I. pseudomeda; B) I. barnumiae subsp. barnumiae; C) I. meda; D) I. barnumiae subsp. demawendica.

FIGURE 6. The different shapes of the fall in three close species of sect. Oncocyclus. A) I. meda (3.2−5 × 1.5−2.1 cm); B) I. barnumiae subsp. barnumiae (3.4−7 × 1.3−3.8 cm); C) I. pseudomeda (3.5−4 × 0.8−1.5 cm).