Polygonum elazigense Behçet, 2025

Polygonum elazigense Behçet View in CoL , sp. nov. ( Figs. 1–5 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 and 8 View FIGURE 8 , Table 1).

Type: — TÜRKİYE. B 8 Elazığ: Karakoçan District, 12–13 km west-northwest of the district center, the oak ( Quercus libani and Q. petrae subsp. pinnatiloba ) forest openings (steppe slopes) between Üçbudak Village and Dede Hamlet, 1300–1400 m, 21 September 2024, Behçet & Gülbasan 1515 (holotype BIN!).

Diagnosis ( Figs. 1–7 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 View FIGURE 6 View FIGURE 7 , Table 1): — Polygonum elazigense resembles P. luzuloides Jaub. & Spach and P. setosum Jacq. but it by its biological form (shrubby vs. suffrutescent with hard woody stocks), its height (up to 115 cm vs. to 40 cm), the lower parts of the stems are very thick, lignified, brown or gray in color and have peeling bark (vs. virgate, indurated, unpeeled), leaves (30–70 × 2.5–13 mm wth flat margins (vs. 20–40 × 5 mm, with revolute margins), stems (below the inflorescence are very branched vs. slightly branched or no branching), pedicel length (1.5–6.0 mm vs. 1–2 mm), flower length (3.5–5.0 mm vs. to c. 3 mm), nut length (5.0– 5.5 mm, clearly longer than the perianth vs. to 3 mm, shorter than perianth).

in bold.

Description: —Erect shrub, up to 115 cm tall, with a hard thick woody root. Stems branched, erect, glabrous, its 40–50 cm lower parts thick (up to 13 mm diameter), lignified, with brownish, partly peeled fibrous bark; the upper parts greenish, relatively thin and unpeeled. Ochreae tubular, to 23 mm long in lower nodes, shortening upwards (to 3– 4 mm), the lower parts brown, prominent many-nerved, upper parts (towards the tip) hyaline, fringed at apex. Leaves shortly (0.3–2.5 mm) petiolate, lanceolate, broadly lanceolate or narrowly elliptic, acute, 30–70 × 2.5–13 mm, margins flate, green-greyish-green, adaxial surface prominently veined, the bracts much abbreviated (2–12 × 0.3–0.5 mm, linear-lanceolate), the uppermost obsolescent. Inflorescence widely branched spica or panicula sometimes the flowers in rather distant fascicles. Flowers whitish, pale roseate (the lower part greenish in late period), axillary, surrounded by ochrea, (2–)3– 4 at each node. Pedicels 1.5–6.0 mm long, unequal, greenish or pinknish. Perianth campanulate, the lower parts greenish (especially in the late period), edges and upper parts white, pinkish white, segments green or pink-veined, 3.5–5 mm (the segments obovate, 2.5–3.5 × 1.5 mm, the tube 1-1.5 long). Stamens 8, shorter than perianth; anthers 0.5–0.6 × 0.4–0.5 mm, yellow; filaments 1.2 mm long, white, expanded at base. Ovary 1 mm long, style 3, thick, 0.4–0.5 mm long, stigma capitate. Nut 5.0– 5.5 mm long, smooth, 3 -angled greenish, greenish brown, clearly exserted from the perianth.

Etymology: —The epithet of the new species derives from locus classicus (Elazığ Province).

Proposed vernacular name: —Since no local name is known, the name “ Elazığ madımağı” is suggested, referring to the Elazığ Province, where the new species epithet is based ( Menemen et al. 2016).

Phenology: —Flowering time August October; fruiting time October November.

Habitat and ecology:— Polygonum elazigense grows in oak forest [dominated by Quercus libani G.Olivier and Q. petraea (Matt.) Lieb. subsp. Pinnatiloba (K.Koch) Menitschy] at 1300–1400 m a.s.l. Other associated species are: Cynanchica stricta subsp. latibracteata (Boiss.) P.Caputo & Del Guacchio , Astragalus amblolepis Fisch. , Asyneuma limonifolium (L.) Janch. subsp. limoniifolium , Bunium elegans (Fenzl) Freyn , Chaerophyllum macrospermum (Willd. ex Spreng.) Fisch. & C.A.Mey. ex Hohen. , Delphinium kurdicum Boiss. & Hohen. , Dianthus floribundus Boiss. , Erysimum uncinatifolium Boiss. , Euphorbia macroclada Boiss. , Falcaria vulgaris Bernh. , Galium tenuissimum M.Bieb. f. trichophorum (Kar. & Kir.) Ehrend. & Scho ̈nb.-Tem., Helichrysum armenium DC. subsp. araxinum (Takht. ex Kirp.) Takht. , Heptaptera anisoptera (DC.) Tutin , Hypericum scabrum L., Lactuca serriola L., L. viminea (L.) J.Presl & C.Presl, Linaria kurdica Boiss. & Hohen. subsp. kurdica , Onosma gigantea Lam. , Opopanax hispidus (Friv.) Griseb. , Rumex acetosella L., Saponaria glutinosa M.Bieb. , Thymus migricus Klokov& Des-Shost , Stachys sparsipilosa R.Bhattacharjee & Hub.-Mor. , Tanacetum abrotanifolium (L.) Druce, T. cilicium (Boiss.) Grierson , Taraxacum montanum (C.A. Mey.) DC. , Telephium imperati L. subsp. orientale (Boiss.) Nyman , Thymelaea passerina (L.) Coss. & Germ., Torilis arvensis (Huds.) Link subsp. neglecta (Schult.) Thell. , Ziziphora clinopodioides Lam.

Distribution and conservation status:— Polygonum elazigense is here considered as endemic to Eastern Anatolia ( Fig. 8 View FIGURE 8 ) occuring only in the type locality 12–13 km west of the Karakoçan (Elazığ) district center in the Eastern Anatolia region of Türkiye. Factors such as forest destruction in the distribution area of the new species (road opening activities for transportation purposes in the region, construction for shelter, cutting for fuel, cutting of oak branches for animal feed, etc.), erosion, grazing are the most important factors threatening the small population of the new species. Based on the number of localities (one), extent of occurrence (EOO, less than 100 km 2) and area of occupancy (AOO, less than 10 km 2), the IUCN category of this new species is assessed as “Critically Endangered” (CR) according to the criteria B1ab [i,ii,iii] and B2ab [i,ii,iii] ( IUCN 2025).

Taxonomical relationships: — Danser (1927), Steward (1930) Coode & Cullen (1966) stated that morphological characters (such as stem, leaf, flower) are more distinctive in the taxonomy of the genus Polygonum . Polygonum elazigense is very different from its morphologically close species jut based on these features.

Polygonum elazigense resembles P. luzuloides ( Fig. 6 View FIGURE 6 ) and P. setosum ( Fig. 7 View FIGURE 7 ) being perennial, having multiveined and brown basal parts and hyaline ochrea upper parts, the general structure of the flowers, the number and structure of stamens in the flower, the three-angled, smooth nut surface features. However, the new taxon is distinctly different from both species in its vegetative features such as its tall shrubby biological life form feature , its 40-50 cm long and lignified stem structure (thickness up to 13 mm), its flat margined and petiolate leaf structure (dimensions up to 70 × 13 mm) ( Figs. 1–3 View FIGURE 1 View FIGURE 2 View FIGURE 3 , Table 1). On the other hand, P. elazigens does not resemble the mentioned species in terms of its generative structure features such as pedicel (up to 6 mm long), perianth (3.5–5.0 mm long) and nut (greenish color, smooth surface and 5.0– 5.5 mm long) ( Figs. 4–5 View FIGURE 4 View FIGURE 5 , Table 1).

The perianth color of Polygonum elazigense is white, whitish-pink, and especially the lower parts are pink in the early periods of flowering, whereas, in the late period, the lower part becomes greenish. Komarov (1970) and Webb & Chater (1964) stated that the perianth color of the members of the Polygonum genus can vary according to the maturity period of the plant.

Concerning the colour of nuts, it is usually brown or brownish in Polygonum species,; however, in P. setosum and P. luzuloides nuts are blackish while in P. elazigense , nuts are are greenish and distinctly longer. The number of Polygonum species in Türkiye with Polygonum elazigense has reached 35.

Key to Polygonum elazigense View in CoL and similar perennial Turkish taxa: — It follows:

1. Bracts much shorter than the stem leaves; stems strict, ± erect ......................................................................................................... 2 1. Bracts about the same size as the stem leaves; stems decumbent to prostrate, lax ............................................................................6 2. Leaves elliptic, up to 2 times longer than broad; lower ochreae bifid or weekly laciniate ............................................... P. icaricum View in CoL 2. Leaves linear to lanceolate, more than 3 times longer than broad;lower ochreae strongly laciniate ................................................ 3 3. Stems branched below the inflorescence; leaves more than 5 mm wide ........................................................................................... 4 4. Plant, up to 40 cm long, stems thin, 1–3 mm thick, bark not peeled, leaves revolute, sessile, nut 2–3 mm long........... P. luzuloides View in CoL 4. Plant, up to 115 cm tall, lower 40–50 cm of stem lignified, 5–10 mm thick, bark partially peeled, flat, shortly petiolate, nut 5–5.5

mm long........................................................................................................................................................................... P. elazigense View in CoL 3. Stems unbranched below the inflorescence; less than 5 mm wide..................................................................................................... 5 5. Plant glaucous; perianth eglandular, shorter than the bract................................................................................................ P. setosum View in CoL 5. Plant ashy grey; perianth with a few pink glands, exceeding the bract........................................................................ P. praelongum View in CoL 6. Leaves mucronate; flowers sessile, fasciculate, forming a dense inflorescence ..................................................... P. paronychioides View in CoL

Paratypes: — TÜRKİYE. Elazığ: Karakoçan District, 12-13 km west-northwest of the district center, the oak ( Quercus libani and Q. petrae subsp. pinnatiloba ) forest openings (steppe slopes) between Üçbudak Village and Dede Hamlet, 1300–1400 m, 22 June 2024, Behçet & Gülbasan 1401 (BIN!); ibidem 19 October 2024, Behçet & Gülbasan 1519 (BIN!).