Centaurea zagrosmontana Ranjbar & Heydari, 2016

Ranjbar, Massoud & Heydari, Razayeh, 2016, A taxonomic contribution to yellow-flowered members of Centaurea sect. Phaeopappus (Asteraceae) in Iran, Phytotaxa 277 (2), pp. 182-190 : 189

3. Centaurea zagrosmontana Ranjbar & Heydari , sp. nov. Fig. 2 .

Diagnosis:—The new species is closest to Centaurea obtusifolia (Boissier & Haussknecht 1875: 599) Wagenitz (1963: 184) ( Turkey) in habit, stem branching, achene size and colour of flowers, but it differs from the latter in stem branched (vs. simple), apex of median and upper stem leaves mucronate (vs. obtuse), cilia colour white (vs. brown to dark brown).

Type:— IRAN. Prov. Kermanshah, Ravansar, 34°42’43 ʺ N, 46°39’4 ʺ E, 1380 m, 14 June 2012, Ranjbar 29055 (BASU!, holotype).

Perennial plants, usually completely green, 38–42 cm tall; collum covered with abundant brown fibrous remains of petioles of previous year; stem branched, erect, densely floccose-tomentose. Leaves large, coriaceous, undivided, broadly oblong to lanceolate, margin entire, mucronate at apex, densely floccose-tomentose. Basal and lower stem leaves pinnatisect, segments in 3–4 pairs, lanceolate to narrowly ovate, entire, obtuse at apex, 12–20 × 2–4.5 cm. Median stem leaves sessile or slightly decurrent, simple, 9–12 × 3–4 cm, broadly sessile or decurrent. Upper stem leaves smaller, sessile or slightly decurrent, simple, 7–16 × 1–3(–5) cm, longer than capitula. Capitule solitary at end of stem, peduncle sessile or 10–30 mm long; involucres oblong, truncate at base, ca. 20 × ca. 35 mm. Phyllaries multiseriate, imbricate, coriaceous to scarious, yellow-greenish, smooth and glabrous. Outer phyllaries ovate, 5–8 × 5–8 mm; appendages 6–8 × 6–10 mm (cilia and spine included). Median phyllaries broadly ovate or broadly oblong-ovate, 10–12 × 10–12 mm; appendages 7–10 × 10–12 mm (cilia and spine included). Inner phyllaries lanceolate or lanceolate-linear, 16–20 × 7–10 mm; appendages 3–4 × 2–3.5 mm (cilia and spine included). Appendages small, concealing a minor part of phyllaries, creamy to straw-coloured, triangular, not decurrent, innermost rounded; cilia white, sublunar, numerous, 8–12 on each side, 5–7 mm long; spine narrowly triangular, 3–7 mm long, equal to cilia. Flowers yellow. Central florets hermaphrodite, ca. 28 mm long, corolla ca. 14 mm long, anther tube pink; peripheral florets sterile, finely dissected, not radiant. Achenes oblong, brown, subglabrous, 6–7 mm long, 3–3.5 mm wide; hilum lateral, ca. 0.8 mm long, glabrous. Pappus 14–17 mm long, scabrous, brownish or straw-coloured.

Etymology: —The species is named after the Zagros Mt. in W Iran, where the new species was found.

Distribution, ecology, climate and habitat:— Centaurea zagrosmontana occurs in mountains at Ravansar, Kermanshah province in W Iran. This species is an Irano-Turanian element. It is a rare endemic, known only from fallow fields and roadsides in the Shahu mountains. It grows below 1500 m above sea level. The climate is warm and temperate in Ravansar. The winter months are much rainier than the summer months. The average annual temperature is 13.8 °C, and precipitation averages 551 mm. The climate here is classified as Csa by the Köppen-Geiger system.

Relationships:— Centaurea zagrosmontana is similar to C. obtusifolia in colour of flowers and achene size, but differs in some important characters (see Table 1).

Figures

FIGURE 2. Holotype of Centaurea zagrosmontana Ranjbar & Heydari (Ranjbar 29055, BASU). A. Habit; B. Inflorescence; C. Outer phyllary; D & E. Median phyllaries; F & G. Inner phyllaries. Scale bars: A = 2 cm, B = 2 cm, C = 1 cm.