Centaurea solitaria Ranjbar & Negaresh (2014a: 53)

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

33. Centaurea solitaria Ranjbar & Negaresh (2014a: 53) . Type:— IRAN. Prov. Kermanshah: Ravansar , 1380 m, 14 June 2012, Ranjbar & Negaresh 28821 (holotype BASU!, isotypes BASU!, photo herb. Negaresh). ( Fig. 73 )

Biennial plants, whole plant usually pale green, 65–80 cm tall; collar of fibrous petiolar remains present at stem base. Stem erect, always simple, yellowish, 6–8 mm in diam. at base, cylindrical, with thin white striations, sparsely leafy throughout, lower part subglabrous to sparsely short hirsute-articulate hairy, median part sparsely covered with hirsute-articulate hairs, up to 0.8 mm long and sessile glands, upper part sparsely arachnoid, sometimes with scattered hirsute-articulate hairs and sessile glands. Leaves rigid, papyraceous (on drying), smallish, rather densely covered with short hirsute-articulate hairs, up to 0.8 mm long, especially along midrib and veins, and sessile glands, margins subscabrous. Basal leaves withered at anthesis, petiolate (up to 10 cm long), lyrate; terminal segment much larger, ovate or lanceolate, 10–13 × 6–8 cm, narrowed toward base, cartilaginously denticulate, acute at apex; lateral segments smaller, or as lobes, 1 pairs, shortly lanceolate or shortly triangular. Lower cauline leaves simple, sometimes withered at anthesis, with a 6.5–11.5 cm petiole, rhombic or rhombic-lanceolate, 18–23.5 × ca. 4.3–4.4 cm, narrowed at each end, denticulate, acuminate at apex. Median cauline leaves sessile, oblong, 7.7–14 × 1.5–2.8 cm, decurrent, up to 30 mm along stem, entire, rarely denticulate, acuminate at apex. Upper cauline leaves successively smaller, sessile, linear or bract-like, 2.7–3 × 0.3–0.65 cm, densely covered with hirsute-articulate and sparsely arachnoid hairs, narrowly decurrent, up to 8 mm along stem. Capitula solitary or 3–5, arranged in a raceme, upper peduncles 3–10 cm long. Involucres broadly ovoid, 35–45 × 32–38 mm. Phyllaries multiseriate, green or reddish above, imbricate, coriaceous, with densely tomentose hairs. Appendages medium-sized, concealing a major part of phyllaries, chartaceous, not decurrent; cilia narrowly triangular, subreflexed, numerous, 4–8 on each side, (1.5–) 3–10 mm long; spines narrowly triangular, 5–9 mm long, longer than or ± equal to adjacent cilia. Outer phyllaries oblong, 3.5–5 × 5–6.5 mm; appendages triangular, 13–14 × ca. 12 mm (including cilia and spine), straw-coloured. Median phyllaries oblong-lanceolate, 7–11 × 8–9.5 mm; appendages triangular, 16–18 × 13–16 mm (including cilia and spine), brownish. Inner phyllaries lanceolate, 15–20 × ca. 10 mm; appendages narrowly lanceolate, 15–18 × 9–14 mm (including cilia and spine), brown to purple. Flowers purple-pink; central florets hermaphroditic, 48–50 mm long, corolla ca. 16–17 mm long, 5-lobed, lobes 7.2–8 mm long, with yellow nerves, style longer than corolla, stigma exserted from corolla, up to 6 mm; peripheral florets sterile, equal to or slightly longer than central ones, numerous (ca. 20 in each capitulum) and conspicuous, finely dissected, not radiant, 4-lobed, limb lobes linear, ca. 8 mm long. Achenes oblong, 6.3–7.3 mm long, 3.2–3.8 mm wide, smooth and shiny, yellowish, rounded at apex, glabrescent; insertion areole lateral, 0.7–1 mm long. Pappus persistent, multiseriate, scabrous, whitish, 13–14 mm long, bristles of inner rows slightly shorter than others.

Taxonomic and distribution remarks: — Centaurea solitaria is a narrow endemic to Kermanshah Province, W Iran ( Fig. 72 ). It is an Irano-Turanian element, and grows on stony slopes, along river, green hills and fallow fields, at elevations of 1350–1450 m. Centaurea solitaria shows some affinity with C. regia var. cynarocephala in its texture of appendages, length of spine and cilia, and somewhat color of appendages. However, it differs from C. regia var. cynarocephala by its lower cauline leaves rhombic or rhombic-lanceolate, ca. 4.3–4.4 cm wide, narrowed at each end, denticulate (vs. broadly lanceolate, 10–12 cm wide, sometimes narrowed toward base or broadly decurrent along petiole, undivided or basally pinnatilobed), upper peduncles 3–10 cm (vs. 10–15 cm) long, involucres broadly ovoid, 35–45 × 32–38 mm (vs. subglobose or globose, 40–55 × 40–60 mm), phyllaries densely tomentose (vs. glabrous), appendages medium-sized, concealing a major part of phyllaries, triangular or narrowly lanceolate (vs. large, totally concealing phyllaries, ovate or broadly triangular), median appendages 16–18 × 13–16 mm (vs. ca. 20–25 × 20–25 mm), cilia subreflexed, 4–8 on each side (vs. erect, 10–17 on each side), and also in the pappus: bristles of inner rows slightly shorter than others (vs. bristles of inner rows much shorter than others, 2–5 mm long).

Chromosome numbers: —Unknown.

Selected specimens examined:— IRAN. Prov. Kermanshah: 25 km to Ravansar, 1450 m, 25 June 2012, Ranjbar & Negaresh 28848 ( BASU!) (paratype of Centaurea solitaria ); Ranjbar & Negaresh 28842 ( BASU!) (paratype of Centaurea solitaria ); Ravansar toward Kamyaran, 1–3 km after Ravansar, 1375 m, 29 May 2014, Negaresh & Kamalnejad 20135 ( HUI!, herb. Negaresh!).

Figures

FIGURE 72. Distribution of Centaurea shehbazii (circles), C. solitaria (squares), and C. spicata (triangles).

FIGURE 73. Centaurea solitaria Ranjbar & Negaresh (Ranjbar & Negaresh 28821, BASU). A. habit. B. outer phyllaries. C and D. median phyllaries. E–G. inner phyllaries. H. indumentum of median part of stem.