Polygonum terzioglui S.Makbul, Coskunç. & S.Kundakçi, 2023

Makbul, Serdar, Kundakçi, Suzan, Gültepe, Mutlu, Güzel, Murat Erdem & Coşkunçelebi, Kamil, 2023, Polygonum terzioglui sp. nov. (Polygonaceae), from Northeast Turkey, Phytotaxa 625 (3), pp. 248-264 : 250-253

Polygonum terzioglui S.Makbul, Coskunç. & S.Kundakçi , sp. nov. ( Figs. 1 2 ).

Type: — TURKEY. Sinop, Inceburun , 25 m a.s.l., 16 October 2022, Makbul and Kundakçı 514 (holotype RUB!; isotypes KTUB!, RUB!, ANK!, KATO!) .

Diagnosis: — Polygonum terzioglui is morphologically similar to P. samsunicum , but it mainly differs from P. samsunicum ; the tepal color is white to slightly pinkish in young plants (not red-pinkish), whereas they are white in mature plants (not pinkish-white), ochrea divided near the apex (not near the base), 21 27 nerved ochrea (not 10 18), obovate-broadly elliptic leaf (not elliptic, lanceolate, linear, oblong elliptic), and ovate-narrowly ovate fruit (not broadly ovoid).

Description:— Perennial, suffrutescent with a hard-woody stock. Stem prostrate, 19–62 cm, simple or somewhat branched at apex, glabrous, white striate. Leaf 13 20 × 4 8 mm, coriaceous, obovate broadly elliptic, sessile or shortly petiolate, undulate and at hyaline margins, subacuminate, adaxial surface prominently veined. Ochrea 4.5 10 (̶ 11) mm long, ovate, light brown at base membranous at apex, 21 27 nerved. Inflorescence lax racem. Flowers axillary, 2 3 at each node. Pedicels 2.5 4.0 mm long, unequal, surrounded by ochrea. Perianth is campanulate, tepals (in young plants) white-slightly pinkish, whereas tepals are white in mature plants. Bracts similar to and about the same size as the stem leaf. Tepals 5, 2 3.5 × 1 1.4 mm, elliptic to oblong, obtuse at apex. Stamens 8, 0.5 1.4 mm, filaments dilated at base; anthers yellow, 0.2 0.4 mm; ovary ovate, 0.5 1 mm, style 3, 0.3 0.4 mm, stigma capitate, 0.06 0.10 mm. Fruit nuts, trigonous, ovate narrowly ovate, young fruits 3.13 3.94 × 1.21 1.45 mm, mature fruits 1.90 3.00 × 1.05 1.20 mm, dark brown, glabrous, exerted in the persistent perianth.

Eponymy:— The specific epithet refers to in honor of Dr. Salih Terzioğlu, who is a well-known plant taxonomist at the Faculty of Forestry, Karadeniz Technical University, Turkey.

Habitat and ecology:— Polygonum terzioglui grows in moist forest clearings near sea level and shares its habitat with Bellis perennis Linnaeus (1753b: 886) , Carex remota Linnaeus (1754: 24) , Crepis foedita Linnaeus (1753b: 807) , Cynodon dactylon ( Linnaeus 1753a: 58) Pers (1805: 85) var. villosus Grossheim (1928: 91) Juncus littoralis C.A.Mey (1831: 34) , Rubus canescens DC (1813: 139) , Pinus brutia Tenore (1815: 72) and Erica arborea Linnaeus (1753a: 353) .

Flowering time September November; fruiting time October November.

Distribution: — Endemic from North Anatolia ( Fig. 3 ).

Key to Polygonum terzioglui and closely related perennial taxa distributed in Turkey: — It follows:

1. Ochrea not nerved; stem prostrate................................................................................................................................. P. ekimianum

- Ochrea strongly nerved; stem ascending, creeping, decumbent, erect, procumbent or prostrate ......................................................2

2. Number of flowers in fascicle 5 6 ................................................................................................................................. P. afyonicum

- Number of flower in fascicle 2 4.......................................................................................................................................................3

3. Leaf sessile; inflorescence in densely spikes....................................................................................................................... P. melihae

- Leaf subsessile or shortly petiolate; inflorescences in lax spikes.......................................................................................................4

4. Leaf overlapping at the base; tepals ca. 2 mm long ...................................................................................................... P. salebrosum

- Leaf not overlapping at the base; tepals 2 4 mm long.......................................................................................................................5

5. Mature tepals pinkish-white; ochrea 10–18-nerved, divided near the base; fruit broadly ovoid................................ P. samsunicum

- Mature tepals white; ochrea 21–27–nerved, divided near the apex; fruit ovate-narrowly ovate ..................................... P. terzioglui

Distribution and conservation status: — Polygonum terzioglui is endemic to Turkey. It is only known from the type locality around Inceburun (Sinop), northeast of the Turkey ( Fig. 3 ). The AOO is calculated at approximately 1.5–2 km 2. Since the new species is only known from the type gathering, less than 250 mature individuals it should be regarded as “EN” according to the D criterion of the IUCN (2022). Additionally, the population of P. terzioglui is under threat due to bovine breeding, and human commercial activities such as resin harvesting close to the type locality.

Micromorphological properties of leaf, ochrea, and fruit:— Leaf surface (abaxial and adaxial) glabrous; epidermal cells irregular polygonal; anticlinal walls convex and smooth; periclinal walls concave and smooth; epicuticular wax crystalized ( Fig. 4a 1 –a 3 ). Ochrea surface (abaxial and adaxial) glabrous; epidermal cells hexagonal; anticlinal walls convex; periclinal walls concave; epicuticular wax crystalized ( Fig. 5a 1 –a 3 ). Fruit, narrowly trigonous, apex acute, base cuneate, beak 0.2–0.3 mm long; epidermal cells inconspicuous, periclinal walls smooth, surface densely verrucate ( Fig. 6a 1 –a 3 ).

Molecular phylogeny:— The optimal model revealed Gneralised Time Reversible (GTR) under the Akaike Information Criterion (AIC) for nrITS data set. The aligned nrITS matrix of 648 characters, of which 220 were parsimony informative. Simple Indel Coding increased the total number of characters to 749 and the number of parsimony informative characters to 267. The MP analysis resulted in 1 most parsimonious trees (L = 1208, CI = 0.5224, RI = 0.8375, RC = 0.4375, HI = 0.4776). The MP, ML and BI analyses revealed trees with almost identical topology. Therefore, only ML tree with ML, JK, and PP added are presented.

Several members of the tribe Polygoneae namely Atraphaxis , Bactria Yurtseva & Mavrodiev (2016: 42) , Muehlenbeckia , Duma T.M. Schuster (2011a: 1061) , Duravia , Persepolium, Polygonella , Fallopia , and Knorringia (Czukavina 1966: 93) Tzvelev (1987: 76) were selected as outgroup for the phylogenetic analyses. ML tree obtained from nrDNA ITS matrix and BI, ML, and jackknife values were shown in Fig. 7 . As seen in Fig. 7 , members of the Polygonum s.str. ( Polygonum sect. Plebejia , Polygonum, Pseudomollia , and Tephis ) split into two subclades with highly supported (BS = 96, JK = 89, and PP = 1.0) and emerged as monophyletic. The subclade corresponding to the P. sect. Polygonum including the newly described species is fully supported (BS = 100, JK = 100, and PP = 1.0). P. terzioglui appears to be a sister to the remaining taxa of P. sect. Polygonum including P. salebrosum Coode & Cullen (1966: 215) and P. samsunicum however, the supports revealed relationships among the taxa of section are low ( Fig. 7 ).

Figures

FIGURE 1. Polygonum terzioglui (a) photograph from the type locality (Photographed by S. Makbul), (b) holotype (Makbul & S. Kundakçı 514)

FIGURE 2. Polygonum terzioglui (a – a, b – b, c –c, d –d), P. samsunicum (a – a, b – b, c –c, d – d), a. Flower, b. Leaves, c. Ochrea, 1 2 1 2 1 2 1 2 3 4 3 4 3 4 3 4 d. Fruit. Drawing by S. Kundakçı. (sp: spot, oc: ochrea, scale bar: 2 mm.)

FIGURE 3. Distribution map of Polygonum terzioglui, P. samsunicum, and P. salebrosum according to floristic regions of Turkey.

FIGURE 4. (a –a) Polygonum terzioglui (Makbul & S. Kundakçı 514), (b –b) P. samsunicum (Makbul & S. Kundakçı 316). 1. Leaves 1 3 1 3 (stero microscope), 2. Leaves (SEM), 3. epidermal ornamentation (SEM).

FIGURE 5. (a –a) Polygonum terzioglui (Makbul & S. Kundakçı 514), (b –b) P. samsunicum (Makbul & S. Kundakçı 316). 1. Ochrea 1 3 1 3 (stero microscope), 2. Epidermal cell shape (SEM), 3. Ochrea ornamentation (SEM).

FIGURE 6. (a –a) Polygonum terzioglui (Makbul & S. Kundakçı 514), (b –b) P. samsunicum (Makbul & S. Kundakçı 316). 1. Fruit 1 3 1 3 (stero microscope), 2–3. Fruit surface ornamentation (SEM).

FIGURE 7. Majority-rule consensus cladogram of the Polygonum from the ML analysis based on the nrDNA ITS dataset (support values: first-line ML bootstrap and JK jackknife, second-line pp posterior probability). Clade names are in accordance with those taken from Yurtseva et al. (2019), and Atraphaxis, Bactria, Duma, Duravia, Fallopia, Muehlenbeckia, Persepolium, and Polygonella were indicated by a thick black bar.