Centaurea masjedsoleymanensis 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 : 152-160

Centaurea masjedsoleymanensis Ranjbar & Askari , sp. nov. Figs. 1–5 .

Diagnosis:—The new species is close to Centaurea pabotii Wagenitz (1980: 375) in habit, pappus length and colour of flowers, but differs from the latter by having leaves densely hispid-tomentose (vs. sparsely hirsute-articulate or subglabrous), base of upper cauline leaves decurrent for 2–4 mm (vs. not decurrent), median cauline leaves incised, pinnatipartite-pinnatilobate or pinnatifid (vs. entire or repand-dentate and oblong or lanceolate-oblong, semiamplexicaul), upper cauline leaves 1.6–4.5 × 0.2–0.4 (vs. 5–9 × 0.4–0.7 mm), involucres subconical (vs. ovoid), phyllary spines 2–4 mm (vs. 0.8–4.0 mm) long, achene lanceolate-oblong, 2–3 mm long (vs. oblong lanceolate 5–6 mm).

Type: — IRAN. Khuzestan, Masjed Soleyman toward Ramhormoz, ca. Haftkel, 31° 31’ 13’’ N, 49° 34’ 20’’ E, 417 m, 12 April 2017, Ranjbar & Askari (Holotype: BASU 40001).

Perennial plant with thickened rootstock, up to 30–35 cm tall, green or pale green throughout. Stem upright, in lower part densely hispid. Stem many, erect to ascending, often branched in lower to upper parts, slightly striate striped, lateral branches 13–17 cm long bearing a few small leaves and ending in a capitula, 1–2 mm in diam. at base, cylindrical, sometimes ascending, branched often at base or near base, or branched in median part, thinly white striate, rigid, densely leafy throughout. Leaves and stem densely hispid-tomentose, venation actinodromous at basal and lower cauline leaves. Basal cauline leaves pinnatipartite-pinnatilobate or pinnatifid, 19–25 × 6–8 cm, terminal segments larger, elliptic to triangular, lateral segments 4–6 pairs, lanceolate-triangular; segments sometimes lobed near base, acute at apex, margin incised. Lower cauline leaves pinnatipartite-pinnatilobate or pinnatifid, 17–27 × 5–7.5 cm, terminal segments larger than lateral one, triangular, lateral segments 4–7 pairs, oblong-lanceolate; segments sometimes lobed near base, acute at apex, margin incised. Median [lower] cauline leaves pinnatipartite-pinnatilobate or pinnatifid, 10–16 × 0.8–2 cm, decurrent for 4–9 mm, margin incised, venation reticulate. Median [upper] cauline leaves sessile, simple oblong-lanceolate, 6–11.5 × 0.6–1.3 cm, acute to acuminate at apex, decurrent for 3–6 mm, perfoliate, margin dentate. Upper cauline leaves sessile, simple, lanceolate to oblong-lanceolate, 1.6–4.5 × 0.2–0.4 cm, shortly decurrent for 2–4 mm, acuminate at apex, venation parallel, margin entire. Capitula numerous, arranged in a corymb, usually somewhat removed from base of capitula. Involucres subconical, contracted towards top, diamond, 12–20 × 11–17 mm. Phyllaries multiseriate, imbricate, coriaceous, yellowish or green, hairy. Outer phyllaries ovate, 5–7 mm long. Median phyllaries ovate to oblong, 9–15 mm long. Inner phyllaries oblong, 16–17 mm long. Appendages forming a minute deciduous tip, undecurrent, not concealing basal part of phyllaries, fringed in upper part or with 1–2 pairs cilia on each side, 1 mm long, spine triangular, 2–4 mm long, longer than nearest cilia. Flowers yellowish pale green; central flowers hermaphrodite, up to 26 mm long; peripheral sterile, not radiant, limb lobes linear. Achene lanceolate-oblong, 2–3 mm long. Pappus multiseriate, scabrous, outer 4–6 mm long, inner much shorter.

Etymology:—The specific epithet refers to Masjed Soleyman city, where the new taxon was found.

Phenology:—Flowering April to June.

Distribution and habitat:—The new species is known only from the clay soils ( Fig. 6 ). It is distributed at lower altitudes (420 m) in Khuzestan province compared to the other related species ( Table 1). This taxon is restricted to south western Iran and is endemic to the Irano Turanian flora region. Centaurea masjedsoleymanensis grows with Bromus danthoniae Trin. , Centaurea bruguierana (DC.) Hand. -Mazz., Centaurea intricata Boiss. , Carthamus tinctorius L., Onosma bulbotrichum DC. , Reseda aucheri subsp. transitoria Rech. f. , and Vicia michauxii Spreng.

IUCN Red List category: — Centaurea masjedsoleymanensis is known from a few small populations, consisting of no more than 5 plants, observed in a mountain between Haftkel and Naft Sefid village (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.

Relationships: — Centaurea masjedsoleymanensis belongs to C. sect. Microlophus, which includes taxa that are perennials with a taproot; stems branched above with a few to many medium-sized capitula. Leaves simple, lyrate to pinnatifid or pinnatipartite, non-decurrent to decurrent. Involucres oblong-ovoid to subglobose, 12–30 × 13–32 mm, glabrous or arachnoid-tomentose. Appendages triangular and ciliate, decurrent with a ciliate margin, usually ending in a spine; flowers yellow or orange, marginal florets often radiant; achenes medium-sized ( Wagenitz 1975, Kaya & Vural 2007). The new species is morphologically close to C. pabotii . This taxon is compared in Table 1.

Chromosome number:— Centaurea masjedsoleymanensis is a diploid species with the base chromosome number of 2 n = 2 x = 16 ( Fig. 7 ), which agrees with other counts for the section including C. polypodiifolia and C. rigida , but differs from the count x = 9 for C. thracica and x = 17 for C. behen (see Romashchenko et al. 2004).

Figures

FIGURE 1. Centaurea masjedsoleymanensis (Ranjbar & Askari 40001, BASU). A. habit. B. close up of capitule. C and D. median [upper] leaves. Scale A = 5 cm, Scale B, C and D = 1 cm.

FIGURE 2. Centaurea masjedsoleymanensis (Ranjbar & Askari 40001, BASU). A. habit. Scale A = 5 cm.

FIGURE 3. Centaurea masjedsoleymanensis (Ranjba & Askari 40001, BASU). A. close up of capitule. B1–B3: outer phyllaries. C1–C3: median phyllaries. D1–D3: inner phyllaries. E: leaf stomata. F and G: leaf indumentum, Scale A = 1 cm.

FIGURE 4. Centaurea masjedsoleymanensis (Ranjbar & Askari 40001, BASU). A. basal cauline leaves. Scale A = 5 cm.

FIGURE 5. Morphological characters measured in Centaurea masjedsoleymanensis (Ranjbar & Askari 40001, BASU). A. middle stem leaf. B. peripheral floret. C. involucre. D. involucral bract. For character explanations see Table 1.

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.