Centaurea geluensis Boissier & Haussknecht

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

11. Centaurea geluensis Boissier & Haussknecht in Boissier (1875: 674). Type :— IRAN. Prov. Kohgiluyeh and Boyer-Ahmad: in declivitate of mountains, 2400 m, 1 July 1867, Haussknecht s.n. (holotype G!: three sheets comprising one specimen, isotype JE!). ( Fig. 25 )

Biennial plants, whole plant usually grayish-green. Stem erect, branched from median to upper parts, 45–60 cm tall, white, cylindrical, ± densely covered with grayish arachnoid-tomentose hairs. Leaves rigid-chartaceous, with thick white striations, subglabrous, margin scabrous. Basal leaves unknown. Lower cauline leaves 12–24 cm long, with a short petiole, lamina lanceolate in outline, basally lobed, with 3–4 lobes on each side, or lyrate, terminal segment very large, acute at apex, ± lossely grayish arachnoid-tomentose along midrib. Median cauline leaves sessile, simple, lanceolate-oblong or broadly oblanceolate, 4–8 × 2.3–4.8 cm, winged or broadly decurrent, up to 50 mm along stem, rounded, apiculate or acute at apex. Upper cauline leaves smaller, sessile, oblong, oblong-lanceolate or lanceolate-linear, rarely ovate, 1–3.5 × 0.3–1.3(–2.3) cm, broadly decurrent, up to 30 mm along stem, sometimes winged, mucronate or cuspidate at apex. Capitula numerous, arranged in a corymbose dichasium, sometimes with bracts similar to phyllaries with small stramineous and chaffy appendages. Involucres ovoid, truncate at base, 30–35 × 18–25 mm. Phyllaries multiseriate, scarious-coriaceous, imbricate, yellowish in sicco, loosely tomentose, with indistinct nerves in upper part. Appendages rigid-coriaceous, totally concealing phyllaries, straw-coloured or pale brown, ovate-triangular or lanceolate, 5–7 mm wide at base (excluding cilia), not decurrent, ciliate, inner ones lacerate into a short spine or rounded with a denticulate margin; cilia short, numerous, 7–12 on each side, (1–) 1.5–2 mm long; spine narrowly triangular, 5–7 mm long, strongly longer than adjacent cilia. Flowers yellow; central florets hermaphroditic, 25–27 mm long, corolla 12–13 mm long, 5-lobed, lobes 4–5 mm long; peripheral florets sterile, slightly shorter than central ones, finely dissected, not radiant, 5-lobed, limb lobes filiform, 6–7 mm long. Achenes oblong or oblong-lanceolate, ca. 7–7.5 mm long, ca. 3 mm wide, silver-bronze, sometimes dark brown to blackish, smooth and shiny, glabrous; insertion areole lateral, large and distinct, yellow, ca. 1.8 mm long. Pappus double, persistent, multiseriate, pale brown, sometimes whitish, scabrous, ca. 3.5–4 mm long, bristles of inner rows shorter than others, ca. 1.5 mm long.

Nomenclatural notes: — There are three sheets at the herbarium G that are original material of Centaurea geluensis . Wagenitz (1960) designated one as a lectotype and the other as isolectotypes. Our study showed that three sheets belong to a single specimen and there is only one specimen at the herbarium G which it must be automatically considered as a holotype .

Regarding the authorship of the name, Index Kewensis, IPNI and Wagenitz (1960) misinterpreted it as Centaurea geluensis Boiss. & Hausskn. ex Boiss. The species was described for the first time in Boissier’s Flora Orientalis ( Boissier 1875) . When the authorship was shared, Boissier wrote both authors in brackets as C. geluensis (Boiss. & Haussk.) (Fl. Orient. 3: 674) that should be interpreted as C. geluensis Boiss. & Hausskn. in Boiss., but certainly not as C. geluensis Boiss. & Hausskn. ex Boiss. (Art. 46.2).

Taxonomic and distribution remarks: — Centaurea geluensis is a very rare endemic to Kohgiluyeh and Boyer-Ahmad Province, SW Iran ( Fig. 26 ). It is an Irano-Turanian element and only known from two close localities in Zagros Mountains (Kuh-e Saverz). Centaurea geluensis grows on rocky slopes in a high-montane zone, at elevations of 2400–2700 m. This species occurs in higher elevations than the other species of C. sect. Cynaroides . Centaurea geluensis with C. iranshahrii and C. gudrunensis forms a natural species group within C. sect. Cynaroides marked by morphological characters such as: stem strongly branched from near base to median part, many branches, and dichasium-like inflorescence. In addition, these species also share yellow flowers and subglabrous indumentum.

Chromosome numbers: —Unknown.

Selected specimens examined:— IRAN. Prov. Kohgiluyeh and Boyer-Ahmad : in rupestr. Eshgar mts., 2700 m, Haussknecht s.n. ( JE!) .

Figures

FIGURE 25. Centaurea geluensis Boissier & Haussknecht (Haussknecht s.n., G). A. achenes with pappus. B. habit. C. close up of involucre. Scale A = 2 cm, C = 3 cm.

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