Astragalus makuensis Maassoumi, Bagheri & Rahimin., 2014

Bagheri, Ali, Rahiminejad, Mohammad Reza & Maassoumi, Ali Asghar, 2014, A new species of the genus Astragalus (Leguminosae-Papilionoideae) from Iran, Phytotaxa 178 (1), pp. 38-42 : 39-41

Astragalus makuensis Maassoumi, Bagheri & Rahimin. sp. nov. ( Fig. 1 ).

Type :— IRAN. W . Azarbayejan province: Maku, ca. 10 km on the road from Chaldoran to Khoy , 38° 59´21.01”N, 44° 25´24.88”E, 2150 m, 03 July 2012, Maassoumi and Bagheri 98385 (holotype TARI, isotypes Herbarium of the University of Isfahan, MSB) .

Paratypes:— IRAN. W. Azarbayejan province: Maku, ca. 10 km on the road from Chaldoran to Khoy , 38° 59´21.01”N, 44° 25´24.88”E, 2150 m, 03 July 2012, Maassoumi and Bagheri 98380, 98384 , TARI, Herbarium of the University of Isfahan ).

Diagnosis: —Differt ab Astragalus hymenocystis Fisch. & C. A. Mey. stipulis 13–20 mm (nec ad 8–13 mm) longis, foliis 2–8 cm (nec 1.5–3 cm) longis, foliolis 4–7 (nec 3–5) jugis, 4–10 × 1–3.5 (nec 3–7 × 2–4) mm, pedunculis 3–12 (nec 2.5–6) cm longis, racemeis ovoideo vel cylindraceis, 3.5–6.5 cm longis (nec globosis to ovoidis, 2.5–3.5 cm longis), petala pallida flava (nec roso–violacea). Ab Astragalus pereshkhoranicus Maassoumi & F.Ghahrem. stipulis 13–20 mm (nec ad 10–13 mm) longis, foliis 2–8 cm (nec 2–3.5 cm) longis, foliolis 4–7 (nec 5–6) jugis, 4–10 × 1–3.5 (nec 5–8 × 1.5–2.5) mm, pedunculis 3–12 (nec 1.5–7) cm longis, racemeis ovoideo vel cylindraceis, 3.5–6.5 cm longis (nec globosis to ovoidis, 2.5–4.5 cm longis), calycis simplicibus dense pilis patentibus vel ascendentibus 4.5 mm longis (nec duplis pilis ascendentibus 1.5–3 mm longis et pilis brevioribus 0.5 mm longis) obtectis, dentibus 5–8 mm (nec 7–12 mm) longis, petala pallida flava (nec violacea), vexillo 16–20 (nec 18–25) mm longo.

Description: —Subshrub, caespitose, ca. 20 cm tall and ca. 50 cm in diameter. Stems in the older parts ligneous, up to 3 cm long, branching from the base and covered with blackish bark and the remnants of the old petioles and stipules; younger stems in the current year ca. 1 cm long. Stipules membranous, hyaline at the apex, 13–20 mm long, narrowly triangular-acuminate, with many fine parallel nerves, adnate to the petiole for 8–10 mm, very shortly connate, ciliate at the margins, otherwise glabrous. Leaves including petiole 2–8 cm; petiole up to 3 cm, both petiole and rachis densely covered with predominantly erect white hairs 1.2 mm long, with few spreading to subappressed hairs 0.3–0.7 mm long. Leaflets opposite, in 4–7 pairs, the indumentum shining silvery and leaflet surface greenish; elliptic, 4–10 × 1–3.5 mm, acuminate, pungent, with a cusp 0.3–1 mm, on both sides densely to very densely covered with subappressed to spreading white hairs 0.4–1 mm and with few long erect hairs up to 2 mm, partly complicate, terminal leaflets modified to a spine. Inflorescence a terminal raceme; peduncle 3–12 cm, brownish, densely covered with erect, tangled white hairs up to 3 mm and with very short spreading hairs 0.2–0.5 mm. Racemes ovoid to cylindrical, 3.5–6.5 cm long, ca. 2–2.5 cm wide, densely many-flowered, the flowers very shortly pedicellate. Bracts partly caducous, elliptic, membranous, hyaline at the margins, acuminate, 11–15 × 4–6 mm, hairy at the base, very rarely in the central part sparsely hairy, ciliate at the margins. Calyx slightly inflated, 13–18 mm long, whitish-yellow, densely covered with erect to spreading hairs up to 4.5 mm; teeth subulate, 5–8 mm, glabrous on inner surface. Petals pale yellowish, glabrous. Standard 16–20 mm long; blade 5–8 mm wide, retuse or rarely emarginate at the apex, obtusely hastateauriculate at base, below the middle slightly constricted, gradually narrowed into the rather wide claw. Wing ca. 18 mm long; blade narrowly oblong to elliptic, obtuse, 5–7 × 1.5–3 mm; auricle ca. 0.2 mm; claw ca. 10 mm. Keel ca. 14 mm long; blade obliquely obovate, subacute, 4–6 × 2–3 mm; auricle indistinct; claw ca. 9 mm. The claws of the wings and the keel are adnate to the staminal tube for 0.5–1 mm. Ovary ca. 13 mm, sessile, hairy, stigma capitate. Stamens ca. 15 mm, diadelphous, 9 + 1, the connate stamens free in the upper 3-4 mm. Fruit unknown.

Etymology: —The specific epithet “ makuensis ” refers to the city of Maku, in the vicinity of the type locality, on the border of Iran-Turkey in W. Azarbayejan province, Iran.

Distribution and Ecology: — Astragalus makuensis is known only from the type locality, in W. Azarbayejan province ( Fig. 2 ). The new species grows on gravelly and rocky mountain slopes between 2150–2200 m elevation, in steppe vegetation of the Irano-Turanian phytogeographic region. It is part of the cushion forming vegetation type.

Phenology: —Flowering June and early July; fruiting July or later

Taxonomic notes: — Astragalus makuensis clearly differs from its most closely related species, A. hymenocystis Fisch. & C. A. Mey. (1853: 449) and A. pereshkhoranicus Maassoumi & F.Ghahrem. (1999: 38) . The diagnostic characters distinguishing A. makuensis from its closely related taxa are summarized in Table 2.

Figures

FIGURE 1. Astragalus makuensis (drawn from holotype). A: Habit, B: Leaflet, C: Bract, D: Calyx, E: Standard, F: Wings, G: Keel, H: Androecium, I: Gynoecium.

FIGURE 2. Distribution map of Astragalus makuensis (●).