Centaurea gigantea Schultz Bipontinus ex Boissier (1875: 672)

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

12. Centaurea gigantea Schultz Bipontinus ex Boissier (1875: 672) . Type:— IRAQ. In apricis lapidosis ad pagum Gara Kurdistaniae prope Mossul, 1 August 1841, Kotschy 349 (lectotype G! designated by Wagenitz 1960: 486, isolectotypes E!, FI!, G!: four sheets, HAL!, K!: two sheets, LAU!, M!, MO!: two sheets, P!: six sheets, S!, GOET!, WAG!, W!: five sheets) Centaurea chaldaeorum Nábělek (1925: 40) . Type:— TURKEY. Kurdistania turc. distr. Ramorân, ad pagum Šernach (Şirnak) ad septentrionem ab oppido Ğeziret-ibn-Ömar (Cizre), in steppe inter frutices Quercuum, 1200 m, 24 Juy 1910, Nábělek s.n. (holotype

BRA!).

Biennial plants, usually green all over, with a thick turnip-like root, (30–) 60–180 cm tall; collar of fibrous petiolar remains present at stem base. Stem erect, simple, sometimes branched in lower part, 5–10 mm in diam. at base, cylindrical, with thick yellow to green striations, lower to median parts ± densely covered with long hirsute-articulate hairs, up to 3 mm long, upper part loosely to densely cover with arachnoid hairs, sometimes mixed with hirsute hairs. Leaves rigid, papyraceous (on drying), loosely covered with hirsute-articulate hairs, denser along midrib and veins, sometimes upper ones mixed with arachnoid or only ± densely covered with arachnoid hairs. Basal leaves with a long petiole (up to 18 cm long), usually withered at anthesis, oblong-cordate, subcordate or broadly lanceolate, lamina 13–24 × 7–15 cm, remotely serrulate, sometimes entire, acute at apex. Lower cauline leaves with a short petiole, lanceolate, entire, acute at apex. Median cauline leaves sessile, simple, lanceolate, oblong or oblanceolate, sometimes narrowed toward base, 10–22 × 3–7 cm, broadly decurrent, up to 42 mm along stem, entire, acuminate at apex. Upper cauline leaves increasingly smaller, sessile, lanceolate to narrowly lanceolate, 5–10 × 0.5–2.2 cm, broadly decurrent or winged, entire, elongate into a mucro at apex (mucronate). Capitula several, 3 to 7(–12), arranged in a raceme, peduncles short or pedunculate in the upper part, gradually longer towards base, lowest ones sometimes with 2–4 heads. Involucres subglobose or obconical, truncate at base, sometimes convex at base ( “subsp. rechingeri ”), gradually contracted at apex and angustate, 30–35(–45) × (20–)25–30(–45) mm. Phyllaries multiseriate, coriaceous, imbricate, pale green or green-brownish, densely tomentose. Appendages firm, concealing part of phyllaries only, straw-coloured or brown, sometimes dark brown, elongate triangular, sometimes shortly triangular ( “subsp. rechingeri ”), 2–4 mm wide at base (excluding cilia), gradually narrowed into a spine (2–) 5–13 mm; cilia numerous, ± patent, 4–8 on each side, (2–) 3–5 mm long. Outer phyllaries triangular, 2–3.5 × 2–3 mm, appendages 6.5–8.2 × 8–9 mm (including cilia and spine). Median phyllaries broadly lanceolate or lanceolate, 14–16 × ca. 10–11 mm, appendages 12–18(–20) × 7.5–12 mm (including cilia and spine). Inner phyllaries lanceolate-linear or linear, 27–31 × 4–10 mm, appendages 14–17 × 3–6 mm (including cilia and spine). Flowers purple or pink, sometimes pale pink (sulphur in sicco); central florets hermaphroditic, 34–36 mm long, corolla 15–16 mm long, 5-lobed, lobes 6–7 mm long; peripheral florets sterile, slightly shorter than central ones, numerous (15–20(–25) in each capitulum) and conspicuous, finely dissected, slightly radiant, 5-lobed, limb lobes linear. Achenes oblong, 5.5–7(–8) mm long, 2.5–3.5 mm wide, whitish or brownish, smooth and shiny, glabrous; insertion areole lateral, yellow or brown, 0.8–1.1 mm long. Pappus double, persistent, multiseriate, brown or whitish, scabrous, pappus (5–)8–10(–13) mm long, bristles of inner rows much shorter than others.

Taxonomic and distribution remarks: — Centaurea gigantea generally occurs in Arbil, Kirkuk, Mosul and Sulaymaniyah Province, from N to NE Iraq ( Fig. 26 ). There are also a few populations in Hakkari Province, SE Turkey ( Fig. 26 ). It is an Irano-Turanian element, and grows on dry rocky slopes, fallow field and roadsides, or stony plains, at elevations of 700–2000 m. Recently, Ghahreman & Attar (2000) reported this species from Lurestan Province as new to Iran, but we doubted the validity of this report that may belong to C. amadanensis subsp. amadanenis .

Centaurea gigantea is similar to C. spicata in its indumentum of stem and leaves, shape of median and upper cauline leaves, and shape of inflorescence. However, it differs from C. spicata by its basal and lower cauline leaves undivided, oblong-cordate, subcordate or broadly lanceolate, lamina 22–24 × ca. 10 cm (vs. lyrate, broadly triangular to lanceolate, lamina 6–16 × 6–28 cm), involucres subglobose or obconical, gradually contracted at apex and angustate, 30–35(–45) × (20–)25–30(–45) mm (vs. ovoid, 25–28(–32) × (17–) 20–25 mm), appendages straw-coloured or brown, sometimes dark brown, elongate triangular, sometimes shortly triangular, 2–4 mm wide at base (excluding cilia) (vs. ovate-lanceolate to narrowly triangular, sometimes lanceolate-triangular, brown, rarely straw-coloured, (3–) 4–6 mm wide at base (excluding cilia)), cilia 4–8 (vs. 7–10) on each side, flowers 34–36 mm (vs. 28–32 mm) long, and also achenes 5.5–7(–8) mm (vs. 4–5 mm) long.

Figures

FIGURE 26. Distribution of Centaurea geluensis (circles), C. gigantea subsp. gigantea (squares), and C. gigantea subsp. rechingeri (triangles).