Astragalus taleshensis Bidarlord, F. Ghahrem. & Maassoumi, 2016

Bidarlord, Mahmoud, Ghahremaninejad, Farrokh & Maassoumi, Ali Asghar, 2016, A new species of the genus Astragalus (Leguminosae) from Northwest Iran, Phytotaxa 252 (4), pp. 280-284 : 281-284

Astragalus taleshensis Bidarlord, F. Ghahrem. & Maassoumi , sp. nov. ( Figs. 1–2 )

Astragalus taleshensis is closely related to A. khajiboulaghensis Maassoumi , but differs by its stipules being triangular, 5–7 mm long, with white hairs, sometime glabrous, leaflets 6–11(12) pairs, both sides densely covered with sub-appressed white hairs, bracts 5–6 mm, calyx 11–13 mm long, petals violet and fading to yellowish in lower parts, banner 15–16 × 5–6 mm, wings 12–13 mm, keel 13–14 mm.

Type: — IRAN. Ardabil province: 50 km south Khalkhal, Aq-Dagh protected area, between Miyanroodan and Lerd villages, Palangah Mountain, 37°23′ N, 48°38′ E, 2500 m, 20 June 2014, Bidarlord 15883 (holotype: T, isotype: FAR, TARI).

Perennial, 4–8 cm long, acaulescent or shortly caulescent, caespitose. Caudex up to 35 mm long, branched, with remnants of old stipules. Stems shorter than 1 cm, covered by stipules. Stipules 5–7 mm long, triangular, at the base ca. 2 mm adnate to the petiole and jointed one another, midribs distinct, covered with appressed white hairs up to 1 mm long, sometimes glabrous at the base. Leaves 2–4 cm long; petiole 1.5–2.5 cm long, both petiole and rachis, covered with long and short spreading or sub-appressed white hairs up to 1.5 mm long; leaflets 6–11(–12) pairs, narrow elliptic, 4–7 × 2–3 mm, cunate at the base, acute at the apex, both sides densely covered with sub-appressed white hairs up to 1.5 mm long. Inflorescence with 7–15 flowers; peduncle 2–4.5 cm long, covered with long and short spreading white hairs, hairs up to 2 mm, denser than on the rachis, and spreading hairs mixed with black hairs toward the inflorescence; racemes dense, 1.5–3.5 cm long. Bracts herbaceous, linear-lanceolate, 5–6 mm long, papery, with black and white hairs, hairs up to 2 mm. Flowers sub-sessile, pedicel 0.5–1mm long. Calyx tubular, 11–13 mm long, covered densely with sub-appressed, black and white hairs, the teeth 4–5 mm long, linear pilose hairs up to 3 mm long. Corolla violet, in dry becoming pale violet to yellowish at lower parts, glabrous; banner (standard) 15–16 × 5–6(–7) mm, the limb rhomboid, recurved through 60°–70° emarginated at the apex; wings 12–13 × 2.5–3 mm, the claw 8–9 mm long, the limb 5–6 mm long, narrowly-oblong, rounded at the apex, auriculate at base, auricle rounded, 1 mm long; keel 13–14 × 2–3 mm, the claw ca. 10 mm long, the limb 5 mm long, obliquely oblong, subacute; auricle minute, 1 mm long. Stamens 13 mm long; anthers ca. 0.6, elliptic, yellow. Ovary 4 mm long, sessile, with long tangled white hairs; style glabrous, 10 mm long. Pod ca.10 × 3–4 mm, straight, shortly stipitate at the base, stipe 1 mm long, fusiform, rounded and carinate ventrally, deeply sulcate dorsally, fully bilocular, coriaceous, At first green then becoming bark brown, densely lanate, white hairs spreading up to 6 mm; beak 3–4 mm long. Ovule 1; Seed ca. 3 × 2 mm, smooth, brown.

Etymology:— The specific epithet of the new species refers to the type locality in Talesh Mountains, northwest Iran.

Conservation status:— The data gained from field studies were evaluated according to the IUCN (2014) Red List categories and criterion. A. taleshensis is known only from one sub-population (criterion B2a), the extent of occurrence (EOO) and area of occupancy (AOO) are less than 10 km 2 (criterion B1–B2).The total number of individuals of this endemic species does not exceed 80–100 in its locality (criterion C). In addition, many grazing herds occupied the area. Therefore, A. taleshensis should be evaluated as critically endangered (CR) and, a conservation plan for the threatened species is needed.

Distribution and habitat: — A. taleshensis is currently known only from its type locality ( Fig. 3 ).This remarkable new species is a narrowly endemic species from northwest Iran, and is an Irano - Turanian element. These plants grow in the subalpine belt, at the elevation of 2500–2700 m.a.s.l., on high inclination thorn-cushion grasslands and scree ground.

Phenology:— Flowering from May to July, fruiting from June.

Taxonomic relationship s: — As well as having the characters of its section, A. taleshensis according to its morphological characters like the plant’s habit and indumentum, especially, the petiole and rachis being covered with long and short white sub-appressed hairs, limb of the banner rhomboid, emarginate, and its fruiting characters, similar to A. khajiboulaghensis that grows in north Ardabil province in Iran. A. khajiboulaghensis differs from A. taleshensis in having stipules ovate, 4–5 mm long, dense black-hairy, 11–16 pairs of leaflets, bracts 8–10 mm long, calyx 14–15 mm long, banner 19–20 × 6–7 mm, wings ± 16 mm long, keel 15mm long and petals yellow ( Table 1).

Section diversity:— According to Flora Iranica ( Podlech et al. 2010) this section is an extremely difficult species-rich section. In addition to the new species, some other species belonging to section Malacothrix occur in the Talesh Mountains such as A. Beckii Bronmüller (1908: 5) , A. elegans Bunge (1868:55) , A. eriopodus Boissier (1843: 48) , A. iranicus Bunge (1868:56) , A. pauperiflorus Bronmüller (1908: 4) , A. macrourus Fischer & C.A. Meyer (1838: 346) and A. podocarpus C.A. Meyer (1831: 142) .

Figures

FIGURE 1. Habit of Astragalus taleshensis.

FIGURE 2. Astragalus taleshensis; A. Stipules, B. Petiole, C. Peduncle, D. Calyx, E. Banner, F. Wing, G. Keel, H. Stamina, I. Ovary, J. Pod.

FIGURE 3. Distribution of Astragalus taleshensis (●) in Iran.