Centaurea obtusifolia (Boiss. & Hausskn.) Wagenitz (1963: 184)

Ranjbar, Massoud & Negaresh, Kazem, 2013, A revision of Centaurea sect. Phaeopappus (Asteraceae, Cardueae), Phytotaxa 123 (1), pp. 1-40 : 25-26

11. Centaurea obtusifolia (Boiss. & Hausskn.) Wagenitz (1963: 184) . Fig. 12 .

Basionym: Phaeopappus obtusifolius Boiss. & Hausskn. in Boissier (1875: 599). Tomanthea obtusifolia (Boiss. & Hausskn.) Takhtajan (1939: 243) . Type: TURKEY. In monte Gebel Taktak (Tektek Da.) Mesopotamiae, May 1867, Haussknecht s.n. (holotype G!, isotype JE!, photo BASU!).

Perennial plants, usually completely greyish; stem simple, erect, densely covered with canescent-arachnoid appressed hairs, monocephalous. Leaves large, coriaceous, undivided, broadly oblong to lanceolate, margin entire, obtuse at apex, densely canescent-arachnoid. Basal and lower cauline leaves unknown. Median cauline leaves sessile, simple, 19–21 × 3.8–7 cm, broadly decurrent up to 40(–50) mm along stem. Upper cauline leaves smaller, sessile, simple, 7–16 × 1–3(–5) cm, broadly decurrent up to 42 mm along stem, slightly longer than capitula. Capitula solitary at end of stem, peduncle 11–20 mm long; involucres subglobose, truncate at base, ca. 20 × ca. 35 mm (in juvenile state). Phyllaries multiseriate, imbricate, coriaceous-scarious, yellowbrownish, smooth and glabrous. Outer phyllaries ovate, 5–7 × 5–6 mm; appendages ca. 6 × ca. 5 mm (cilia and spine included). Median phyllaries broadly ovate or broadly oblong-ovate, 13–17 × ca. 13 mm; appendages ca. 7 × 5–6 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, brown to dark brown, triangular, not decurrent, innermost rounded; cilia brown, sublunar, numerous, 4–8 on each side, 1–3 mm long; spine narrowly triangular, 2–4 mm long, slightly longer than the nearest cilia. Flowers yellow. Mature achenes unknown.

Taxonomic and distributional remarks: — Centaurea obtusifolia is endemic to E Turkey. It is an Irano- Turanian element, known only from the mid-montane zone ( Wagenitz 1975). Centaurea obtusifolia is a very rare species and is known only from the type locality. It is similar to C. spectabilis in the shape of involucres and appendages but differs in its indumentum densely canescent-arachnoid (vs. tomentose-canescent), median and upper cauline leaves broadly decurrent and obtuse at apex (vs. not decurrent and short cuspidate or mucronate at apex), median cauline leaves simple, 19–21 cm long (vs. pinnatisect to pinnatifid, often with few asymmetric lobes only in the upper half, or undivided, 8–12 cm long), cilia 1–3 mm (vs. 3–5 mm) long, and also spine 2–4 mm (vs. 3–6 mm) long.

In addition, C. obtusifolia shares some characters such as indumentum canescent-arachnoid and all leaves undivided with C. hellwigii , but differs from it in having its median and upper cauline leaves broadly oblong to lanceolate, broadly decurrent up to 50 mm (vs. broadly lanceolate to elliptic or lanceolate, not decurrent), median cauline leaves 19–21 cm (vs. 5.4–12 cm) long, upper cauline leaves slightly longer than capitula (vs. shorter than capitula), involucres subglobose (vs. ovoid), appendages brown to dark brown (vs. strawcoloured to light brown), and also spine slightly longer than the nearest cilia (vs. equal to nearest cilia).

Chromosome numbers: —Unknown.

Figures

FIGURE 12. Centaurea obtusifolia (Boiss.& Hausskn.) Wagenitz (Haussknecht s.n., JE). A. habit. B. phyllaries. Scale A and B = 2 cm.