Primulina nanlingensis J. C. Luo & H. F. Chen 2025, sp. nov.

Primulina nanlingensis J. C. Luo & H. F. Chen sp. nov. Figs 2, 3 Type. China • Guangdong Province, Yingde City, Shimentai National Nature Reserve, 23°28′N, 113°05′E, 620 m elev., growing on top of a cliff on a limestone hill, 7 May 2024 (fl.), J. C. Luo & H. F. Chen LJC 00501 (holotype: IBSC; isotypes: IBSC). Diagnosis. The new species is similar to Primulina versicolor F. Wen, B. Pan & B. M. Wang in terms of flower shape and corolla colour, but easily distinguished from the larger leaf blades (10–21 × 7–19 cm vs. 8–18 × 6.5–16.5 cm) with a crenate margin (vs. entire); notably lower number of flowers (3–4 cymes, 4–8 flowered vs. 4–8 cymes, 4–24 flowered or more); bracts ovate-lanceolate (vs. broadly oval or suborbicular), with shallowly serrate margins above the middle (vs. entire margins); calyx lobes densely glandular on both surfaces (vs. outside glandular-pubescent inside nearly glabrous) and with 1–3 inconspicuous teeth each side (vs. 3–5 - serrate); longer pistil (3.2–3.5 cm vs. 2.5–2.8 cm) and glandular-puberulent (vs. puberulent); filaments white (vs. pale yellow) with densely glandular at base and tip, sparser mid-section (vs. only upper half sparsely glandular-puberulent). Additionally, while the leaf morphology of this new species resembles that of P. pengii W. B. Xu & K. F. Chung, it differs in having a longer corolla length (4.2–5.2 cm vs. 2.8–3.6 cm), pale yellow corollas (vs. white) and ovate-lanceolate bracts with slightly serrate edges above the middle (vs. cordate bracts with entire margins). Description. Herbs, perennial rhizome subterete, 5–8 cm × 1.5–2.5 cm, internodes indistinct. Leaves 6–8, opposite at top of rhizome; blade green, succulent to thickly chartaceous, ovate or broadly ovate to elliptic, 10–21 × 7–19 cm, apex obtuse or subacute, margin crenate, base slightly oblique or symmetrical, leaf surface and petiole densely pubescent, abaxial surface densely villous and the veins on the abaxial surface densely pubescent; lateral veins 4–6 - nerved on each side; petiole cross section sub-semicircular or compressed, 2.5–9.5 cm × 0.8–1.5 cm. Cymes axillary, 3–4, 4–8 flowers per cyme; bracts 2 opposite, ovate-lanceolate, 4.1–4.4 cm × 2.2–2.4 cm, outer side is shallowly serrate, apex acuminate, outside pubescent, inside sparsely pubescent; peduncle 5–12.5 cm long, 4–6 mm across, densely pubescent; pedicel 1.2–2.8 cm long, glandular-puberulent. Calyx 5 - lobed nearly to the base, 8–15 mm × 1.6–2.5 mm, lanceolate, light green, both surfaces densely glandular-puberulent, with 1–3 inconspicuous teeth on each side. Corolla 4.2–5.2 cm long, pale yellow, throat dark yellow with 2 pale purple stripes, with 3 patches at the sinuses of the 2 upper lip lobes, patches light brown outside and dark purple inside, sometimes the dark purple patches absent and these patches are glandular, outside densely glandular-pubescent; tube infundibuliform, 3.2–3.8 cm long, orifice ca. 1.3 cm in diameter; limb distinctly 2 - lipped, adaxial lip 2 - lobed bifid to over the middle, lobes oblong, 5–7 mm × ca. 6 mm; abaxial lip 3 - lobed to one-third from the top, lobes oblong, 4–6 mm × ca. 4 mm. Stamens 2, adnate to 1.3–1.5 cm above the base of the corolla base; anthers elliptic, 2.5–3 mm long, densely glandular; filaments ca. 15 mm long, white, with the base and upper part sparsely covered with glandular-puberulent; staminodes 3, two lateral ones adnate to ca. 1.3 cm above the corolla base, ca. 7 mm long, densely glandular-pubescent, apex bent, the central one adnate to ca. 3 mm above the base of corolla base, ca. 2 mm long, glabrous; disc annular, ca. 1 mm high, yellow, glabrous. Pistil 3.2–3.5 cm long; ovary linear, ca. 1.8–2.2 cm long, densely glandular-puberulent; style 0.8–1.2 cm long, sparse glandular-puberulent. Stigmas 2 - lobed, 2.8–3.6 mm long, shallowly lobed, lobes ca. 1 mm long. Capsule green, mature dark brown, 3.2–4.5 cm × 1.5–2.2 mm, with persistent calyx lobes at base, densely white-villous and pubescent. Phenology. Flowering from late April to early June, fruiting from June to August. Distribution and ecology. Primulina nanlingensis is known only from two separate limestone hills in the Shimentai National Nature Reserve, Yingde City, Guangdong Province, China. Companion species were calcareous herbs such as Selaginella effusa Alston, S. delicatula (Desv.) Alston., Pilea peltata Hance and Ficus sarmentosa var. henryi (King ex Oliv.) Corner etc. Etymology. The species epithet refers to the type locality, the Nanling Mountains. Vernacular name. 南岭报春苣苔 (Chinese name); Nán Lǐng Bào Chūn Jù Tái (Chinese pronunciation). Provisional conservation status. At present, only two populations of Primulina nanlingensis have been discovered on limestone hills in the Shimentai National Nature Reserve, where a substantial area of 35 km 2 has been identified as suitable habitat for the species. The two naturally distributed populations are no more than 10 km apart and each population consists of no more than 100 mature individuals. Currently, the two populations are stable, as the habitat is under protection by the administrators of the scenic area. However, considering the overall low number of individuals across the species populations and the conservation measures in place, it could be provisionally classified as Near Threatened [NT] according to the IUCN Red List Categories and Criteria (IUCN Standards and Petitions Committee 2024). Additional specimens examined. China • Guangdong Province, Yingde City, Shimentai National Nature Reserve, 23°28′N, 113°05′E, 620 m elev., growing on top of a cliff on a limestone hill, 25 May 2024 (fl.), J. C. Luo & H. F. Chen LJC 00502 (IBSC).