Centaurea nallihanense Uysal & Hamzaoğlu, 2016

Uysal, Tuna, Hamzaoğlu, Ergin, Ertuğrul, Kuddisi & Bozkurt, Meryem, 2016, A New Species Of Centaurea (Asteraceae) From Turkey, Phytotaxa 275 (2), pp. 149-158 : 150-154

Centaurea nallihanense Uysal & Hamzaoğlu , sp. nov. ( Figs 1, 2 and 3 )

Type:— TURKEY. B2 Ankara, Nallihan, Osmanköy–Yenice arası, Taşlı yamaçlar, Meşe açıklıkları 395 m, 40º04ʹ39” N, 30º53’41” E, 10 July 2011, Hamzaoğlu 6120 (holotype KNYA).

Planta perennis, basi lignosa. Caules erecti, subsimplices, ad 25–60 cm alti, griseo-tomentosi. Folia albo- vel griseotomentosa, basalia inferioraque brevipetiolata, indivisa. Involucrum oblongum, 15–20 mm longum, 9–13 mm latum. Involucri phylla lanceolata , appendicibus satis reductis, anguste triangularibus, mucrone terminali 0.1–0.3(–0.5) mm longo. Flores flavi, marginales steriles radiantes, hermaphroditi. Achenia lanceolata ad ovoideo, 5–6 mm longa, 2–2.3 mm lata. Pappus cremeo-brunneus, persistens, biseriatus, exterior e setis scabris brevissimis 0.5–0.8 mm longis, interior e setis 4.5–5.5 mm longis.

Perennial herbs with sterile shoots and a woody rootstock producing numerous stems. Stems simple, 20–60 cm tall, erect to ascending, slender, yellowish-green striate, floccose to tomentose and rarely glandular-punctate, ca 1.5 mm in diameter below. Leaves undivided, densely floccose or tomentose, sparsely glandular-punctate, entire and attenuate towards base; basal leaves linear, usually withered at fruiting, sessile, 4–12 × 0.1–0.5 cm; median and upper leaves similar to basal leaves but fairly reduced, linear to filiform, sessile, 2–12 × 0.1–0.4 cm, decreasing in size towards capitula, acute to acuminate. Capitula discoid and slim, solitary at the end of branches. Involucre 15–22 × 8–15 mm, glabrous, narrowly ovoid-oblong; outer phyllaries oblong-ovate, 2–3.5 × 1.5–2.5 mm; median phyllaries oblong-lanceolate, 4–10 × 2.5–4.5 mm; inner phyllaries linear to linear-lanceolate, 12–15 × 1–3 mm; appendages fairly reduced, minutely narrow triangular, thinly hyalineous decurrent along all margines, straw-coloured to creamish-brown in the centre, without cilia and ending in a very weak mucro 0.1–0.3(–0.5) mm long. Florets yellow, 18–20 mm long, longitutionally with reddish striae; corolla tube glabrous, 15–16 mm long, lobes 4–5 mm long, linear. Filaments 3–4 mm long, puberulent; anthers 7–8 mm long. Style 20–22 mm long, shaft 16–17 mm long, stigma 3.5–4 mm long, hairy at base.Achenes oblong-lanceolate, 5–6 mm long, brown or brownish-black, longitudinally irregular with yellow striae, smooth and shiny, glabrous; pappus biseriate, outer 4.5–5.5 mm long, scabrous, creamish-brown, inner 0.5–0.8 mm long, setaceous, creamish or light brown and yellowish-brown at base.

Note:— Centaurea nallihanense is a neoendemic species, which appears fairly nice because of its slim stems, capitulas and phyllaries without thorns. Centaurea nallihanense is mainly similar to C. drabidolia subsp. floccosa in a general way, but its appendages are fairly reduced and simple (not with distinct borders and ciliae). The capitula and appendages of the new species are similar to those in C. sect. Ptosimopappus , but the species can be easily distinguished with linear soft leaves and distinct inner pappus (vs. not firm lanceolate leaves and indistinct inner pappus).

Karyology

The chromosome number of Centaurea nallihanense was found 2 n = 18 in all metaphase plates examined ( Fig. 4 ).

The karyotype formula is 6m + 3sm. The new species is diploid; it has specific karyomorphological features and could be easily separated from the other species discussed here ( Table 1, 2, 3). The karyotype of C. nallihanense consists of mainly metacentric chromosomes with the length ranging from 1.113 to 1.771 μm, and the total haploid chromosome length of 12.909 μm ( Table 2). According to asymmetry indices (AI, A 1 and A 2), the karyotype of the new species consists of symmetric chromosomes with a lower level of chromosomal heterogeneity, with a CV CI value below 10. Variations in the length of chromosomes are moderate within the species (CV CL 13.02) ( Table 3).

1

intrachromosomal asymmetry index; A

2

—interchromosomal asymmetry index; CV

CL

—relative variation in chromosome length; CV

CI

—relative variation in centromeric index; AI—karyotype asymmetry index; DI—dispersion index; Stebbins’ types —classification of karyotypes in relation to their degree of asymmetry according to Stebbins (1971).

Taxa A 1 A 2 CV CL CV CI AI DI Stebbins

Centaurea nallihanense 0.326 0.13 13.023 9.402 1.224 5.17 4A

Molecular and Phylogenetic analyses

Centaurea nallihanense and its relatives were placed in a single clade with a bootstrap value of BS: 100% and PP: 1·00. In this clade are firstly found C. kotschyi and C. drabifolia subsp. floccosa (C. sect. Cheirolepis ) as well as C. nallihanense , which are grouped together with a moderate bootstrap support (BS: 64%) but a high posterior probability based on Bayesian Analyses (PP = 0.99). Centaurea aksoyii shows a close phylogenetic affinity to this clade with strong bootstrap and posterior probability values (BS: 99% PP: 1). Centaurea ptosimopappoides is connected externally with an agreeable parsimony value (68%), but high posterior probability (PP: 0.96). Centaurea ptosimopappa appears at a distant relation with this clade (BS: 100%, PP: 1). Therefore, we concluded that the new species is clearly related to the Cheirolepis -Pseudoseridia complex phylogenetically and positioned with C. kotschyi and C. drabifolia subsp. floccosa .

Figures

FIGURE 2. Centaurea nallihanense. A: Capitulum; B: Involucre; C: Phyllaries; D: Achene and pappus; E: Outer and inner series of pappus.

FIGURE 3. Distribution map of Centaurea nallihanense.

FIGURE 4. Karyomorphology of Centaurea nallihanense, with 2n = 18. A: Metaphase plate; B: Karyogram; C: Ideogram.