Centaurea shahuensis Ranjbar & Negaresh (2013: 430)

Negaresh, Kazem & Rahiminejad, Mohammad Reza, 2018, A revision of Centaurea sect. Cynaroides (Asteraceae, Cardueae-Centaureinae), Phytotaxa 363 (1), pp. 448-450 : 448-450

31. Centaurea shahuensis Ranjbar & Negaresh (2013: 430) . Type:— IRAN. Prov. Kermanshah: 5 km from Ravansar, Bave Geh village , Shahu mountains , 1418 m, 31 Jun 2012, Ranjbar & Negaresh 28689 (holotype BASU!, photo herb. Negaresh). ( Fig. 70 )

Biennial plants, with thick fleshy taproot, whole plant usually green, 90–100 cm tall; collar of fibrous petiolar remains present at stem base. Stem erect, usually simple, ca. 12 mm in diam. at base, cylindrical, greenish or yellowish, with thick white striations, densely leafy in median part, lower part glabrescent, median part sparsely covered with hirsute-articulate hairs and sessile glands or subglabrous, upper part with scattered sessile glands sometimes mixed with a few arachnoid hairs. Leaves coriaceous, papyraceous (on drying), entire, with prominent veins on each side, almost covered with sessile glands and hirsute-articulate hairs, up to 1.2 mm long, more densely along midrib and veins. Basal leaves simple, with a 13–16 cm petiole, almost withered at anthesis, broadly cordate-oblong or broadly cordate-lanceolate, 30–35 × 12–14.5 cm, acute at apex. Lower cauline leaves simple, with a 10–14 cm petiole, broadly subcordate to ovate or broadly cordate-ovate, 27.5–37 × 14–18 cm, loosely covered with hirsute-articulate hairs, sometimes mixed with arachnoid hairs, acute or rounded at apex. Median cauline leaves sessile, broadly oblanceolate or subpandurate, 13.5–25 × 7–12 cm, winged or broadly decurrent, up to 60 mm along stem, loosely covered with hirsute-articulate hairs, rarely mixed with scattered arachnoid hairs, acute at apex. Upper cauline leaves increasingly smaller, sessile, oblong or lanceolate, 6.5–11 × 1.5–4.5 cm, sometimes bract-like, sparsely covered with arachnoid hairs, rarely mixed with scattered hirsute-articulate hairs, broadly decurrent, up to 50 mm along stem, acute or acuminate at apex. Capitula several, 6 to 8, arranged in a raceme, upper peduncles 8–12 cm long. Involucres globose-conical, somewhat convex at base, abruptly contracted at apex and angustate (in flowering state), 35–40 × 32–42(–45) mm. Phyllaries multiseriate, yellow-greenish, reddish at margins, imbricate, coriaceous-scarious, densely covered with lanate-tomentose appressed hairs, up to 0.4 mm long; appendages medium-sized, concealing a minor part of phyllaries, rigid, their base somewhat swelling, not decurrent. Outer phyllaries oblong, 3–7 × 6–9 mm; appendages ovate-triangular, 7–9 × ca. 6–7 mm, margins entire or fringed in upper part, gradually narrowed into a 2–8 mm spine, straw-coloured to pale purple. Median phyllaries broadly ovate, 10.5–12 × ca. 11–12 mm; appendages triangular, ca. 15 × 5–7 mm, margin entire or sometimes with 1–2 cilia (1.2–3 mm long) on each side, irregular, gradually narrowed into a ca. 8 mm spine, purple to straw-coloured. Inner phyllaries broadly lanceolate, 14.5–26 × 10–12 mm; appendages narrowly triangular, subspiniform, 14–17 × 2–3.2 mm, margin entire or sometimes with a cilium (1.2–3 mm long) on each side, irregular, gradually narrowed into a 9–11 mm spine, deep purple. Flowers rose-purple; central florets hermaphroditic, ca. 60 mm long, corolla ca. 19 mm long, 5-lobed, lobes 7.2–8.5 mm long, with orange nerves; peripheral florets sterile, nearly equal to central ones, numerous (15–20 in each capitulum) and conspicuous, finely dissected, not radiant, 4-lobed, limb lobes linear, ca. 6.5–7 mm long. Achenes oblong, 5–5.5 mm long, 2.8–3 mm wide, brownish, rounded at apex, glabrescent; insertion areole lateral, 0.5–0.8 mm long. Pappus persistent, multiseriate, scabrous, whitish, ca. 14 mm long, bristles of inner rows equal to others.

Taxonomic and distribution remarks: — Centaurea shahuensis is a rare endemic to Kermanshah Province, W Iran ( Fig. 68 ). It is an Irano-Turanian element, and grows on stony slopes, fallow fields and roadsides, at elevations of 1400– 1450 m (Ranjbar et al. 2013). Ranjbar et al. (2013) stated that this species is closely related to C. regia var. regia but C. shahuensis is easily distinguished from it by having appendages smaller, narrowly triangular to triangular, brown to purple, entire or with fewer cilia. It shows affinity with C. bavegehensis , C. kabirkuhensis and C. kamalnejadii in its habit.

Chromosome numbers: —Unknown.

Selected specimens examined:— IRAN. Prov. Kermanshah: Ravansar, 2 km from Ravansar toward Kamyaran , 34° 43′ 55.7″ N, 46° 40′ 32″ E, 1345 m, 15 June 2017, Negaresh 176 (herb. Negaresh!, RUH!) .

Figures

FIGURE 68. Distribution of Centaurea sclerolepis (circles), C. sennikoviana (squares), and C. shahuensis (triangles).

FIGURE 70. Centaurea shahuensis Ranjbar & Negaresh (Ranjbar & Negaresh 28689, BASU). A. close up of capitule. B. habit. C. median cauline leaves (shape and indumentum). D. indumentum of upper cauline leaves. Scale A = 1 cm, B and C = 2 cm.