Potentilla sanczirii V. Gundegmaa., G. Onolragchaa & M. Urgamal 2025, sp. nov.

Potentilla sanczirii V. Gundegmaa., G. Onolragchaa & M.Urgamal sp. nov. (Figs 1–3) Holotype: — Mongolia. Uvs Province, Khovd village, Bairamyn Passage (davaa), 49 o 58’00” N, 90 o 56’60” E, elev. 2720 m, at moraine in mountain slopes, 26 July 2021, V. Gundegmaa, Ts. Dashmaa & O. Ganbold. UVS 001. Paratypes: — (all MNG, n = 20) Mongolia. Khovd Province, Munkhkhairkhan Mountain, 46 o 85’98” N, 91 o 50’20” E, elev. 3100 m, mountain slopes with moraine, 10 August 2021, V. Gundegmaa, Ts. Dashmaa & O. Ganbold. 001. All the types of collections were deposited in the Laboratory of Botany, Mongolian National University of Education. Diagnosis: — Potentilla sanczirii can be easily distinguished from the P. nivea and P. evestita the pistil style is elongated cylindrical, and the base has fewer suckers (vs. the tip of the pistil style is narrow, and the base is broader with many suckers), 3–4 (5) big crenete leaf margin (vs. 7–9 crenete teeth and 4–9 dentate teeth, respectively), the upper surface of the leaf covered by entangled pubscense (vs. covered by simple, silky long hairs and covered by both simple and gland hair mixed, respectively). Description: —Terrestrial and perennial plant 4–10 cm high. Caudex multiple, and form small cespitose, covered with dark brown remains of decayed stipules. Stems are usually multiple (1–3), ascending at the base, and rarely erect. Basal always leaves ternate and mid-apex rhombus. Leaf lets margin 3–4 (with five large serrate teeth), leaflets size 0.5–1.5 × 0.5–1 cm. The lower leaflet surface is covered with whitish or grayish tomentose, and the upper leaflet surface is covered with entangled pubescence. Leaf petioles covered with woolly hairs. Stipules are ternate palmately lobed, the upper surface is simple sparse strigose, and the lower surface is grayish tomentose. The inflorescence is uniparous cymose with few flowers. Flowers are small, 5–10 mm in diameter. Calyx covered with piliform hairy. Epicalyx bractlets elongated lanceolate to lanceolate, 0.2 mm long, 0.1 mm wide. Calyx lobe triangle obovate, 0.3–0.5 × 0.2–0.4 mm. Petals yellow, obovate, apex emarginated. Stamens 20 is arranged in two whorls: the outer whorl of stamens with short anther filaments and the inner whorl of stamens with long anther filaments. Carpels many; styles elongated cylindrical, with few suckers. Mature nutlets (achenes) are light green and c. 1 mm long, smooth surface. Remarks: —According to our LDA plot, P. sanczirii had distinct morphological characteristics from species (P. evestita and P. nivea) with similar appearance (Fig. S2). Phylogeny:— In an aspect of phylogeny, P. sanczirii is positioned in the subclade of the main Clade D, with closely related P. strigosa, P. desertorum, P. vanzhilii, etc. (Figs. 1 and S1). Species in this subclade have been distinguished from other Potentilla species by having indels at specific sites in studied fragments of cpDNA. More specifically, they had the ten bp deletion (TTTTCTATCT) on-site between 296 and 305 and the four bp insertion (GTTT) between 594 and 597. Such genetic characteristics suggested that P. sanczirii originated from the late Miocene (approximately 6.50 mya). Etymology: —The specific epithet honors for Sanchir, one of the pioneer botanist Mongolia. Phenology: —Flowers were recorded from June to July, and fruits from August. Distribution and habitat:— Out of 16 phytogeographical regions in Mongolia, P. sanczirii is only found in areas Khovd (Kharkhiraa Turgen Mountain range) and Mongol Altai (Munkhkhairkhan Mountain range). Limited distribution for newly described P. sanczirii might result from a lack of field expeditions. Recently, P. sanczirii has been known only from moraine on mountain slopes above 2700 m elevation. More in detail, it grows as solitary in the mossy communities of rocky slopes and prefers to grow in gravel (Fig S3).