Rhaponticoides lachnopus (Rech. f.) Negaresh, 2015

Negaresh, Kazem, Khoshroo, Sayed Mohammad Reza, Karamian, Roya & Joharchi, Mohammad Reza, 2015, A revision of Rhaponticoides (Asteraceae, Cardueae-Centaureinae) from Iran, Phytotaxa 213 (2), pp. 87-101 : 89-92

1. Rhaponticoides lachnopus (Rech. f.) Negaresh , comb. nov. ( Figs. 1 and 2 )

Basionym: Centaurea lachnopus Rechinger (1940: 152) . Phaeopappus lachnopus (Rech. f.) Rechinger (1947: 285) . Type:— IRAN. Prov. Semnan: Damghan-Semnan, in desertis gyps. prope Sorkheh, 1600 m, 30 June 1937, Rechinger 1244 (lectotype W! designated here by Negaresh, isolectotypes BM!, US!).

Plants perennial, herbaceous, arising from thick rhizomes up to 2 cm in diam., throughout green, 40–80 cm tall, densely covered with white lanate pubescence at base, other parts glabrous; remains of stems of the previous year present. Stems several, 5 to 15, erect, simple, sometimes producing fairly small sterile capitula, relatively sturdy, sulcate, densely leafy in lower part, otherwise without leaves, 4–5(–6) mm in diam. at base. Leaves coriaceous in vivo, rigid in sicco, variable in dissection, distinctly serrate. Sterile leaves petiolate, simple, 18–24 × 4–5 cm, lanceolate or lanceolate-oblong, sometimes lyrate, with 1–3 pairs of segments; terminal segment strongly larger, broadly ovate, oblong or lanceolateovate, 3–14 × 2–8 cm; lateral segments much smaller, lanceolate or oblong. Basal and lower cauline leaves petiolate, lyrate or lyrate-pinnatifid, sometimes undivided, 20–40 cm long, segments in 2–6(–7) pairs, terminal segment 5–8 cm wide. Median cauline leaves subsessile, 6–12 cm long, lanceolate in outline, pinnatifid or lyrate, segments in 2–4 pairs, sometimes undivided. Upper cauline leaves increasingly reduced, sessile, lyrate, with 1–2 pairs of small segments at base, terminal segments larger, oblong, sometimes undivided, 5–7 cm long. Capitula solitary on long peduncles (up to 40 cm long). Involucres subglobose or ovoid-globose, truncate at base, 25–35 × 25–40 mm. Phyllaries multiseriate, imbricate, appressed, glabrous, green-yellowish, becoming dark-brown apically, conspicuously longitudinally striate. Appendages large, concealing the major part of phyllaries, conspicuously longitudinally striate with brown-blackish nerves, membranous-scarious, 5–10 mm wide, pale brown or hyaline, margin entire, flat to slightly undulate. Outer phyllaries suborbicular, 4–7 × 7–9 mm; appendices decurrent. Middle phyllaries broadly oblong or oblong-orbicular, 12–17 × 10–12 mm; appendices decurrent. Inner phyllaries oblong or narrowly oblong, 22–30 × 5–8 mm; appendices not decurrent. Receptacle densely covered with long white bristles. Flowers yellow in vivo, sulphury in sicco; central flowers hermaphrodite, 38–42 mm long, distinctly 5-veined, anther tube pale yellow, exserted; peripheral flowers sterile, with staminodes, 4–5-lobed, the lobes filiform. Achenes transversally wrinkled, 9–10 mm long, insertion areole large. Pappus multiseriate, persistent, 10–13 mm long, rarely inner row shorter.

Taxonomic and distributional remarks: — Rhaponticoides lachnopus is a rare endemic of Semnan Province, N Iran ( Fig. 3 ). According to Wagenitz (1980), the species occurs in a limited area. It grows on clay hills, in mid-montane zones, on gypsum fields, at elevations of 1300–1600 m ( Fig. 2 ). Rhaponticoides lachnopus is similar to R. schmidii in its indumentum, margins of leaves and color of flowers. However, it differs from R. schmidii in the presence of sterile leaves, basal and lower cauline leaves lyrate or lyrate-pinnatifid, sometimes undivided, segments in 2–6(–7) pairs, terminal segment 5–8 cm wide (vs. pinnatisect, segments in 6–8(–9) pairs, decurrent along the rachis, terminal segments (1.5–) 3–5 cm wide), median cauline leaves lyrate or pinnatifid (vs. pinnatisect), appendages concealing the major part of phyllaries, 5–10 mm wide, margin entire, flat to slightly undulate (vs. totally concealing the phyllaries, 14–16 mm wide, strongly decurrent, denticulate, irregular lacerate or strongly undulate), and also pappus 10–13 mm long, usually outer as long as inner (vs. 5–7 mm long, inner pappus with unequal bristles: adaxial bristles 7–10 mm long, abaxial bristles 4–6 mm long). Rhaponticoides lachnopus grows at lower elevations than those of R. schmidii .

Chromosome numbers: —Unknown.

Selected specimens examined:— IRAN. Prov. Semnan: 2–7 km above Sorkheh, 1300–1400 m, 29 May 1975, Rechinger 52155 (E!), 52207 (W!), 52155 (W!: two sheets).

Figures

FIGURE 1. Rhaponticoides lachnopus (Rech.f.) Negaresh (Rechinger 1244, W). A. habit. B. close up of involucre. Scale B = 1 cm.

FIGURE 2. Rhaponticoides lachnopus (Rech.f.) Negaresh; after Wagenitz (1980). A and B. habit and habitat.

FIGURE 3. Distribution of Rhaponticoides bachtiarica (1), R. ruthenica (2), R. lachnopus (3), and R. schmidii (4) in Iran.