Phyllagathis chongzuoensis Zhe Zhang, S.W. Yao & S.Jin Zeng, sp. nov. (崇左ffiḡff) (Fig. 2)

Type: — CHINA. Guangxi (广ffl): Chongzuo City (崇左市), Daxin County (* Ǜ 县), Detian Village (德±村), on limestone slope in secondary broad-leaved evergreen forest, 700 m, 1 May 2021, Zhe Zhang, Shi-Wei Yao & Fei Sun ZZ 0823 (holotype: FJFC!; isotypes: NPH!, IBSC!).

Diagnosis: The new species resembles P. erecta, but differs in having stoloniferous stem with indistinct internodes, basal or sub-basal rosette leaves, shorter petioles, and obovate to suborbicular leaf blades with irregularly denticulate margin.

Perennial herbs. Stems stoloniferous, 3–7 cm long, ca. 0.5 cm in diam., densely ferruginous furfuraceous; internodes indistinct, with conspicuous leaf scars. Leaves in a basal or sub-basal rosette, decussate, 2 or 4 pairs; petiole 0.7–1.2 cm long, densely ferruginous furfuraceous, adaxially flattened; leaf blade obovate to suborbicular, 7.0–15.5 × 6.0– 9.5 cm, stiffly papery, base cuneate, apex subrounded, margin irregularly denticulate, adaxial surface usually dark green, sparsely yellow glandular and densely white puberulent when young, glabrescent later, abaxial surface sometimes purple when young, then turning to green, densely ferruginous furfuraceous on veins and sparsely yellow glandular; secondary veins 2 on each side of the midvein, one suprabasal conspicuous; tertiary veins numerous, parallel, and connecting with secondary veins. Inflorescences terminal, umbellate paniculate, 3–17-flowered; peduncle yellowishgreen, 4-sided, 14–16 cm long, sparely furfuraceous. Pedicel 4-sided, 0.5 cm long, granulate. Hypanthium greenish, campanulate to cup-shaped, slightly 4-ribed, ca. 0.4–0.5 × 0.3 cm, sparsely ferruginous furfuraceous, granulate at lower part. Calyx lobes green, triangular-semiorbicular, ca. 1.5 mm long, sparsely ferruginous furfuraceous. Petals pink, oblong to broadly obovate, 4.8–5.5 × 4.0– 4.3 mm, apex obtuse to slightly oblique. Stamens 4; filaments 2.0– 2.5 mm long, glabrous; anthers narrowly ovate to lanceolate, ca. 2.0 mm long, pale yellow, slightly curved; connective decurrent, basally with a dorsal short spur. Ovary half-inferior, ovoid, 1.8–2.1 mm long, apex sparsely glandular trichomes; placentas shortly stalked. Capsules cup-shaped, 4-ribed, ca. 3.0 × 3.0– 3.5 mm (when dry). Seeds numerous, brown, cuneate, ca. 1.0 × 0.6 mm (when mature), densely tuberculate, with a short beak, raphe distinct.

Phenology:— Flowering was observed in May to June. Fruiting started in June.

Etymology:— The specific epithet is derived from the city name of the type locality.

Geographical distribution:— Currently, P. chongzuoensis is only found in Chongzuo, Guangxi, China.

Habitat and ecology:— The new species grows in secondary broad-leaved evergreen sparse forests at an elevation of 700 m as a lithophytic herb on cliffs composed of eroded sandstone on steep slopes.