Centaurea imperialis Haussknecht ex Bornmüller (1906: 168)

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

16. Centaurea imperialis Haussknecht ex Bornmüller (1906: 168) . Type:— IRAN. Prov. Kermanshah: Kangavar, Rasband mountains, 15 July 1896, Strauss s.n. (lectotype B! designated by Wagenitz 1960: 478, isolectotypes B!, G!, JE!: three sheets, W!, Z+ZT!). ( Figs. 33–35 )

Biennial plants, whole plant usually grayish-green or fresh green, with thick and napiform root, 30–150(–180) cm tall; collar of fibrous petiolar remains present at stem base. Stem erect, stout, simple, sometimes branched from near base to median part, 4–15 mm in diam. at base, densely leafy throughout, cylindrical, with green or yellowish striations, densely covered with long grayish-hirsute-articulate hairs, up to 5 mm long. Leaves coriaceous, papyraceous (on drying), usually fresh, undivided, densely covered with hirsute-articulate hairs, sometimes on upper ones mixed with arachnoid hairs. Basal and lower cauline leaves large, sometimes withered at anthesis, with a 15–18 cm petiole, simple, subcordate to cordate-lanceolate, cordate-oblong or broadly lanceolate, lamina 18–22 × 14–17 cm, entire or denticulate, subacute or acute at apex; lower ones narrowed toward base or broadly decurrent along petiole, smaller, ca. 10 × 4 cm. Median cauline leaves sessile, simple, broadly lanceolate, lanceolate or lanceolate-oblong, (10–)15–25 × 4–15 cm, broadly decurrent, up to 65 mm along stem, sometimes winged, entire, acuminate, rarely obtuse or rounded at apex. Upper cauline leaves increasingly smaller, sessile, simple, lanceolate or narrowly lanceolate, 3–12(–16) × 1–4(–6) cm, broadly decurrent, entire, acuminate or mucronate at apex. Capitula numerous, 5 to 15(–25), arranged in a spike or raceme, uppermost ones sessile or with short peduncles, lowermost ones with longer peduncles, sometimes with 2–5 heads. Involucres subglobose, 30–40 × (25–) 30–40 mm. Phyllaries multiseriate, coriaceous, imbricate, green-yellowish, loosely tomentose. Appendages medium-sized, chartaceous, totally concealing phyllaries, suborbicular, broadly ovate or triangular, not decurrent, white, rarely straw-coloured, innermost brown to dark brown, ciliate or regularly fringed; cilia numerous, 10–15(–16) on each side, 1–4(–5) mm long; spine short, 1–3(–4) mm long, ± equal to nearest cilia. Outer phyllaries oblong or rectangular, 3–6 × 3.5–6 mm, appendages 7–10 × 9–15(–16) mm (including cilia and spine). Median phyllaries oblong or rectangular, 6–12 × 6.5–8.5 mm, appendages 11–15 × 17–20 mm (including cilia and spine). Inner phyllaries oblong-linear or linear, 14–28(–29) × 3–9 mm, appendages 7–15 × (3–) 7–16 mm (including cilia and spine). Flowers wine-red in vivo, purple in sicco; central florets hermaphroditic, 36–38 mm long, limb 16–18 mm long, 5-lobed, lobes 6–7 mm long, style ± equal to corolla, stigma exserted part from corolla, up to 4 mm long; peripheral florets sterile, slightly shorter than central ones, numerous (20–25 in each capitulum) and conspicuous, finely dissected, rarely radiant,, 4–5-lobes, limb lobe narrowly linear to filiform, ca. 7 mm long. Achenes oblong or lanceolate, 5–7 mm long, 3–4 mm wide, brownish or whitish, sometimes bronze-silver, smooth or striate, glabrous and shiny; insertion areole lateral, yellow, 0.8–1 mm long. Pappus double, persistent, multiseriate, scabrous, pale brown to brown, rarely whitish, (5–) 6–9 mm long, bristles of inner rows much shorter than others, up to 2 mm long.

Taxonomic and distribution remarks: — Centaurea imperialis generally occurs in Azerbaijan, Hamedan, Kermanshah, Kurdistan and Lurestan Province, from W to NW Iran ( Fig. 36 ). There are also a few populations in Sulaymaniyah Province, NE Iraq ( Fig. 36 ). It is mainly distributed along the border between Iran and Iraq ( Fig. 36 ). Centaurea imperialis with C. amadanensis have a wider distribution in comparison to the other species of C. sect. Cynaroides that are growing in Iran ( Figs. 5 and 36 ). It is an Irano-Turanian element, and grows on roadsides or fallow fields, clay slopes, Quercus brantii forest, mid-montane zone or subalpine plains, at elevations of 1100–2000 m ( Fig. 3A ). During our expeditions in Iran, we noted that there is some trend to growing on disturbed lands. Centaurea imperialis is the only species of C. sect. Cynaroides with that wine-red flowers ( Figs. 34 and 35 ). It is a very beautiful plant and can be used as ornamental ( Fig. 34 ).

Centaurea imperialis is similar to C. regia var. regia in the shape of involucres, texture and status of appendages and number of cilia. However, it differs from C. regia var. regia by its stem indumentum densely long grayish-hirsutearticualte hairs, up to 5 mm long (vs. arachnoid-tomentose hairs, finally glabrescent, sometimes lower part sparsely hirsute-articulate hairs), capitula arranged in a spike or raceme, uppermost sessile or with short peduncles, lowest with longer peduncles (vs. arranged in a raceme, upper peduncles 10–15 cm long), involucres 30–40 × (25–) 30–40 mm (vs. 40–55 × 40–60 mm), median appendages 11–15 × 17–20 mm (vs. ca. 20–25 × 20–25 mm), inner appendages brown to dark brown (vs. white or straw-coloured), cilia 1–4(–5) mm (vs. (3–) 4–6 mm) long, spine of median appendages 1–3(–4) mm (vs. (8–) 9–14 mm) long, flowers wine-red, 36–38 mm long (vs. pink, ca. 45 mm long), and also pappus (5–) 6–9 mm (vs. 10–13(–15) mm) long.

Chromosome numbers: — Garcia-Jacas et al. (1998) and Ghaffari & Shahraki (2001) reported the same chromosome number 2 n = 2 x =18 for Centaurea imperialis .

Selected specimens examined:— IRAN. Prov. Azerbaijan: Oshnavieh to Orumieh , before Agh Bolagh , 15 km after Oshnavieh , 1980 m, 23 June 2009, Ranjbar & Negaresh 18228 ( BASU!) ; Piranshahr, Tamarchin, Iran-Iraq border, 1755 m, 20 June 2012, Ranjbar & Negaresh 31061 ( BASU!) ; trifurcate of Sardasht-Piranshahr, 500 m to Kuper village, 6 July 2014, Negaresh & Asadbegy 133 (herb. Negaresh!); Negaresh & Asadbegy 134 (herb. Negaresh!); Piranshahr toward Oshnavieh , 5 km after Piranshahr, 6 July 2014, Negaresh & Asadbegy 143 (herb. Negaresh!); Oshnavieh toward Orumieh, Agh Bolagh bifurcate, 50 km to Silvana, 6 July 2014, Negaresh & Asadbegy 20131 ( HUI!) ; Negaresh & Asadbegy 141 (herb. Negaresh!); Negaresh & Asadbegy 142 (herb. Negaresh!); Negaresh & Asadbegy 45554 ( FUMH!) ; above Sardasht, 1100 m, Rechinger 49118 ( E!) ; between Balanesh and Oshnavieh , 1650– 1900 m, 11 July 1974, Rechinger 49287-a ( E!) ; Takht-e Soleiman, 17 August 1884, Knapp s.n. ( JE!, WU!); Mianeh toward Khalkhal , 75 km to Khalkhal , 37° 33′ 49″ N, 48° 5.73′ 43.6″ E, 1570–1580 m, 22 June 2015, Negaresh & Pakzad 181 (herb. Negaresh!, HSB!) . Prov. Kurdistan: 5 km from Baneh to Sardasht , 1500 m, 21 July 2012, Ranjbar & Negaresh 28886 ( BASU!) ; 15 km from Marivan to Chanareh , 1404 m, 21 June 2012, Ranjbar & Negaresh 31729 ( BASU!) ; NE Sanandaj, 35 km to Divandareh, 5 July 2014, Negaresh & Asadbegy 144 (herb. Negaresh!); Negaresh & Asadbegy 145 (herb. Negaresh!); Dehgolan toward Sanandaj , 30 km to Sanandaj , beginning Salavat Abad neck, near police station, 5 July 2014, Negaresh & Asadbegy 20133 ( HUI!) ; Negaresh & Asadbegy 135 (herb. Negaresh!); Negaresh & Asadbegy 136 (herb. Negaresh!); Negaresh & Asadbegy 137 (herb. Negaresh !); Baneh toward Sardasht , 50 km to Sardasht , near Abolhasan village , 6 July 2014, Negaresh & Asadbegy 20132 ( HUI!) ; Negaresh & Asadbegy 138 (herb. Negaresh!); Negaresh & Asadbegy 139 (herb. Negaresh!); Negaresh & Asadbegy 140 (herb. Negaresh !); Marivan toward Chenareh , near Kanemat village , 35° 49′ 40″ N, 46° 14′ 51″ E, 2000 m, 25 June 2014, Rahiminejad & Negaresh 20141 ( HUI!) ; Rahiminejad & Negaresh 158 (herb. Negaresh!); 50 km W Sanandaj toward Marivan (Dez Shahpur), 1800 m, Rechinger 42878 ( W!) , 5 July 1971, Lamond 4515 ( E!: two sheets), 54 km N Sanandaj , 2000 m, 2 July 1971, Lamond 4455 ( E!) ; Hossein Abad, 50–60 km N Sanandaj , 2000 m, Rechinger 42744 ( W!) . Prov. Lurestan: E Khorram Abad, Khorram Abad toward Sepid Dasht , 18 km to Bisheh waterfall, 1950 m, 31 May 2014, Negaresh & Asadbegy 20134 ( HUI!) ; Negaresh & Asadbegy 146 (herb. Negaresh!); Negaresh & Asadbegy 147 (herb. Negaresh!); 50 km E Khorram Abad , 1800 m, 1937, Koeie 711 ( B!, C!, W!); Chyrsan mountains , August 1868, Haussknecht s.n. ( JE!) ; Bahram Abad village , 1890, Sawyer 13089 ( E!) ; 1890, Sawyer 13018 ( E!) . Prov. Hamedan: Nahavand, Kuh-e Gerru , 2 August 1908, Strauss s.n. ( B!) . IRAQ. Prov. Sulaymaniyah: ad pedem M. Ouraman , 1500 m, Haussknecht s.n. ( JE!) ; Haji Umran, Guest & Husham 15904 ( K!) ; Rawi & Serhang 24933 ( K!) ; NE of Rayat , subalpine plains, 1480 m, 4 October 1933, Zohary s.n. ( HUJ!) .

Figures

FIGURE 3. Different habitats on the Centaurea sect. Cynaroides. A. C. imperialis. B. C. regia. C. C. nemecii. D. C. alfonsoi. E and F. C. amadanensis.

FIGURE 5. Distribution of Centaurea amadanensis subsp. amadanensis (circles), C. amadanensis subsp. gymnoclada (squares), and C. amadanensis subsp. ranjbarii (triangles).

FIGURE 33. Centaurea imperialis Haussknecht ex Bornmüller (Strauss s.n., B)

FIGURE 34. Centaurea imperialis Haussknecht ex Bornmüller (Ranjbar & Negaresh 28886, BASU). A. close up of capitule. B. inflorescence (upper capitula). C. basal and lower cauline leaves. Scale A = 2 cm, B = 4 cm, C = 5 cm.

FIGURE 35. Centaurea imperialis Haussknecht ex Bornmüller (Ranjbar & Negaresh 28886, BASU). A. immature capitula. B. capitule (with above view). C. inflorescence (the upper and lowest capitula). D. habit and indumentum. Scale A = 3 cm, C and D = 4 cm.

FIGURE 36. Distribution of Centaurea imperialis.