Centaurea palanganensis Ranjbar & Askari, 2018

Ranjbar, Massoud, Askari, Ali & Sw, Someh Mohammadi, 2018, A contribution to Centaurea sect. Microlophus (Asteraceae, Cardueae) in Iran, Phytotaxa 361 (2), pp. 151-167 : 160-166

Centaurea palanganensis Ranjbar & Askari , sp. nov. Figs. 8–11 .

Diagnosis:— Centaurea palanganensis is similar to C. thracica ( Janka 1872: 178) Gugler (1908: 201) in cauline branching and colour of inner phyllaries, but differs from the latter by having median cauline leaves decurrent for 12–18 mm (vs. 5–7 mm), upper cauline leaves entire (vs. crenate), upper cauline leaves ovate (vs. oblong to lanceolate), involucres 7–20 × 6–15 mm (vs. 30–40 × 30–35 mm), median phyllaries 10–13 mm (vs. 13–14 mm) long, median cauline leaves oblong or elliptic (vs. ovate to oblong), spine up to 2 mm (vs. up to 5 mm) long.

Type:— IRAN. Kurdestan, Tefin before Palangan village, 35° 05’ 02’’ N, 46° 36’ 58’’ E, 1097 m, 5 May 2016, Ranjbar & Askari (Holotype: BASU 39100).

Perennial plant, 60–80 cm tall, usually pale green throughout. Stem erect, densely leaved, simple or with 2–4 branches in upper part, mostly branched in lower to upper parts, predominately striate striped, thickened below capitula, densely covered with hirsute-articulate hairs. Leaves papyraceous, ± densely covered with hirsute-articulate hairs, margins scabrous. Basal and lower cauline leaves petiolate, 10–13 cm long, lyrate; terminal segment large, oblong to triangular or ovate, 7–13 × 4–10 cm; lateral segments smaller, in 2–3 pairs, oblong-lanceolate or lanceolate-triangular, 4–5 × 1.5–2.5 cm. Median cauline leaves simple, oblong or elliptic, 6–8 × 1.2–3 cm, decurrent for 12–18 mm, acute or acuminate at apex, margin crenate to sinuate, venation reticulate. Upper cauline leaves ovate 1.5–3 × 0.2–0.9 cm, acuminate to mucronate at apex, margin entire, uppermost ones slightly enveloping involucres. Involucres ovoidcupuliform or broadly ovoid, truncate at base, 0.7–2 × 0.6–1.5 cm long. Phyllaries multiseriate, imbricate, coriaceous, yellowish green, glabrous; outer phyllaries ovate, 5–7 mm long, yellowish green. Median phyllaries oblong to elliptic, 10–13 mm long, yellowish green. Inner phyllaries oblong, 14–16 mm long, pale purple in middle. Appendages a simple spine, 1–2 mm long in median phyllaries, deciduous. Marginal flowers sterile, not radiant, central flowers hermaphrodite, up to 12 mm long; peripheral sterile, not radiant, up to 22 mm, limb lobes linear. Achenes 4–5 mm long. Pappus 5–6 mm long, inner row very short, multiseriate, whitish, scabrous.

Etymology:—The specific epithet refers to Palangan village, where the new taxon was found.

Phenology:—Flowering April to June.

Distribution and habitat: — Centaurea palanganensis occurs in Palangan area, a mountainous region and a village in Zhavehrud Rural District, in Central District of Kamyaran County, Kurdestan Province, Iran. Phytogeographically it is an Irano-Turanian element and grows in dry clay, stony slopes and screes, at elevations of 1000–2000 m ( Fig. 6 ).

Relationships:— Centaurea palanganensis is characterized with median cauline leaves decurrent, upper cauline leaves ovate, margin entire, and inner phyllaries pale purple. It is similar to C. thracica in the colour of flowers and size of basal and lower cauline leaves, but differs in some important characters (see Table 1).

IUCN Red List category:— Centaurea palanganensis is known from a few small populations, consisting of no more than 15 plants, observed in a mountain between Palangan and Tefin villages (M. Ranjbar, pers. obs.). According to the IUCN Red List criteria ( IUCN 2001), this species could be classified as Critically Endangered (CR D). This category includes taxa for which fewer than 50 mature individuals exist.

Chromosome number:— Centaurea palanganensis is a diploid species with the base chromosome number of 2 n = 2 x = 16 ( Fig. 7 ).

Figures

FIGURE 6. Distribution of 1. Centaurea masjedsoleymanensis. 2. C. palanganensis, in Iran.

FIGURE 7. Representative meiotic cells of Centaurea masjedsoleymanensis A–G and C. palanganensis H–O. A. diakinesis. B. anaphase I with bridge. C. telophase I. D. anaphase II. E. metaphase I with precocious chromosome. F. anaphase I. G. anaphase I with bridge. H. anaphase I with bridge. I & J. metaphase I with precocious chromosome. K. diakinesis. L. metaphase I. M. anaphase I. N. anaphase I with laggard. O. bivalent at diakinesis.

FIGURE 8. Centaurea palanganensis (Ranjbar & Askari 39100, BASU). A. habit. Scale A = 5 cm.

FIGURE 9. Centaurea palanganensis (Ranjbar & Askari 39100, BASU). A. habit. Scale A = 5 cm.

FIGURE 10. Centaurea palanganensis (Ranjbar & Askari 39100, BASU). A. close up of capitule. B1–B3: outer phyllaries. C1–C3: median phyllaries. D1–D3: inner phyllaries. E: leaf stomata. F: leaf indumentum, Scale A = 1 cm.

FIGURE 11. Morphological characters measured in Centaurea palanganensis (Ranjbar & Askari 39100, BASU). A. middle stem leaf. B. peripheral floret. C. involucre. D. involucral bract. For character explanations see Table 1.