Lysimachia nanshanensis C. Xiong & S. R. Yi, 2025

Lysimachia nanshanensis C. Xiong & S. R. Yi sp. nov.

Figs 2 View Figure 2 , 3 View Figure 3

Diagnosis.

Lysimachia nanshanensis belongs to ser. Paridiformes F. H. Chen & C. M. Hu ( Chen and Hu 1979: 36) and is similar to L. sciadantha C. Y. Wu ( Wu 1965: 53) by sharing some morphological characters, such as the middle and lower leaves bract-like and opposite, upper leaves clustering at the stem top, flowers densely on umbel. But differs from L. sciadantha in leaves 4–6 (vs. 4) in a whorl, subpapery (vs. stiffly papery), elliptic, ovate to obovate (vs. elliptic), apex obtuse to mucronate (vs. acute to short acuminate), umbels terminal without peduncle (vs. peduncle 1.8–6 cm long), pedicel 3–6 cm (vs. 1.2–2.5) long, filaments almost free (vs. base tube 3–3.5 mm).

Type.

China • Hunan: Chengbu, Nanshan National Park (南山国家公园), Yu’nüxi (玉女溪), 20 April 2019, 26°11'05"N, 110°11'38"E, elev. 750 m, on the rock wall of the valley, Si-Rong Yi YSR 8168 ( holotype, KUN!; isotypes, KUN!, CGMC!) GoogleMaps .

Description.

Perennial herbs. Rhizome short, with many roots up to 15 cm long. Stems erect, often 3–4 - noded, up to 30 cm long, pale pink when young. Leaves opposite, lower and middle ones bract-like; upper ones 4–6 in a terminal whorl, subpapery, with obviously black glandular punctate and striate, elliptic, ovate to obovate, 4.5–11 × 2.0– 4.5 cm, petiole 4–8 mm long and pale purple; leaf blades apex obtuse to mucronate, base cuneate and descending into petiole, margin entire to shallowly undulate; blades adaxially pale green, densely light purple short glandular stripes, abaxially pale greenish; veins sunken adaxially, protuberant abaxially, lateral veins 4–6 pairs. Cauline bracts ovate-lanceolate, 5–11 × 2.5–4 mm. Umbels terminal, many flowers; pedicel slender, 3–6 cm long, pale green, sparsely coated, peduncle absenced. Calyx 5 - lobed, pale purple brownish to green purple; lobes lanceolate, entire, glabrous, 6.5–7.5 mm long, 1.5–1.8 mm wide in middle, apex acuminate, abaxially sparsely light purple short glandular stripes. Corolla broad campaniform to trumpet-shaped, yellow; tube 0.3–0.5 mm, lobes 9–13 × 3.5–4.5 mm, apex undulated to 2–3 - lobed shallowly. Stamens 5, subequal, yellow, 5–6 mm long, filaments almost free, often curved, slightly farinose; anthers elliptic, dorsifixed, 1.2–1.5 mm long, 0.5–0.6 mm wide, opening by lateral slits. Ovary globose, glabrous, 1.2–1.5 mm in diam., style 3.6–4.5 mm, erect. Capsule globose, 1.6–2 mm in diam., style persistent.

Phenology.

Flowering from April to May and fruiting from July to August.

Etymology.

The specific epithet ‘ nanshanensis ’ refers to the type locality where the new species was found, Nanshan National Park, Southwest Hunan. The Chinese name is “ 南山落地梅 (nán shān luò dì méi) ”.

Distribution and habitat.

Lysimachia nanshanensis C. Xiong & S. R. Yi was found only in Yu’nüxi and Shilipingtan, Nanshan National Park, Chengbu County, Hunan, China (Fig. 4 View Figure 4 ). It grows on rocky cliffs within the valley at elevations of 750–1200 m.

Additional specimens examined.

Lysimachia sciadantha : China • Guizhou Province, Xishui, Changqian’gou , Bijie expedition 1701 ( HGAS 0078263 , GZAC 0018115 ) , Suiyang, Kuankuoshui , Yi Li 9306318 ( ZY 0030002 ) ; • Chongqing Municipality, Jiangjin, Simian Mountain , Z. Y. Liu 183194 ( PE 01861962 ) ; • Sichuan Province, Xuyong , X. F. Gao et al. HGX 10826 ( CDBI 0234655 ), X. F. Gao et al. HGX 11693 B ( CDBI 0226619 ) .

Conservation assessment.

Lysimachia nanshanensis is currently known from the type locality, consisting of approximately three populations with 800 mature individuals. The estimated extent of occurrence (EOO) and area of occupancy (AOO) of the new species are approximately 30,000 m 2 and 1200 m 2, respectively. This species grows on rocky cliffs in the valley, an area largely undisturbed by human activity. Furthermore, its distribution falls within Nanshan National Park, affording it a degree of natural protection. Based on the IUCN Red List Categories and Criteria ( IUCN 2025), the species is temporarily assessed as Vulnerable (VU D 1).