Primulina longiflora B.M.Wang & Y.H.Tong, 2025

Tong, Yi-Hua, Ni, Jing-Bo & Wang, Bing-Mou, 2025, Primulina longiflora (Gesneriaceae), a new species from Guangxi, China, Phytotaxa 683 (3), pp. 296-300 : 297-299

Primulina longiflora B.M.Wang & Y.H.Tong , sp. nov. ( Fig. 1 ).

Type: — CHINA. Guangxi Zhuang Autonomous Region: Nandan County, Baxu Xiang, on rocks of limestone hills, elev. 650 m, specimens were made from cultivated plants in the greenhouse of the third author in Guangzhou, 9 July 2024 (fl.), Y. H. Tong, J. B. Ni & B. M. Wang TYH-2899 (holotype IBSC).

Diagnosis: —This new species is morphologically similar to P. curvituba B. Pan, L.H. Yang & M. Kang in Yang et al. (2017: 578), in the shape and texture of the leaf blades and the curved corolla tube, but mainly differs in having longer calyx lobes (6–7.5 mm vs. 2–3 mm), salverform and sigmoid (vs. infundibuliform and almost V-shaped) and much longer (4.5–5 cm vs. 2–2.8 cm) corolla, and bifid (vs. obtrapeziform) lower stigma lobe ( Table 1).

Description: —Perennial herb. Rhizomatous stem subterete, 2–2.5 cm long, 7–9 mm in diameter. Leaves 29–35, congested at rhizome apex; petiole 5–6 × ca. 2 mm, densely white pubescent; leaf blade fleshy when fresh, thickly papery when dried, oblanceolate, 2.5–3 × 1.1–1.2 cm, both surfaces densely white pubescent, apex subacute to obtuse, base cuneate, margin nearly entire and revolute, usually tinged with purple towards to the apex, with purple spots at the junction of lateral veins and leaf blade margin; lateral veins 3–4 on each side, abaxially raised and conspicuous, adaxially slightly impressed and inconspicuous. Cymes axillary, 1–4-flowered; peduncles 4–9.5 cm long, densely white pubescent; bracts 2, opposite, linear, 2.5–4 × ca. 1 mm, margin entire, apex acute, densely white pubescent abaxially, glabrous adaxially. Pedicel 1.5–3 cm long, densely white pubescent. Calyx 5-parted to near base; lobes lanceolate, 6–7.5 × 0.8–1 mm, densely white pubescent abaxially, glabrous adaxially, margin entire. Corolla light blue-purple outside, with five purple lines inside along joints between corolla lobes, salverform, 4.5–5 cm long, glandular-pubescent outside, glabrous inside; lobes blue-purple; corolla tube sigmoid, 4–4.5 cm long, bent upwards at base, then gently curved downwards at 2/3 of the tube, finally bent upwards near the mouth, 2–3 mm in diameter at base, 1.5–2 cm in diameter at mouth; limb indistinctly 2-lipped; adaxial lip 2-parted, lobes broadly oblong, 8–9 × 6–7 mm, rounded at apex, margin slightly praemorse; abaxial lip 3-lobed, lobes broadly oblong, 9–10 × 7–8 mm, rounded at apex, margin slightly praemorse. Stamens 2, adnate to ca. 2.5 cm above corolla tube base; filaments linear, ca. 8 mm long, white, slightly sigmoid, glandular-pubescent; anthers dark purple, elliptic, fused by entire adaxial surfaces, ca. 1.5 mm long, glabrous; staminodes 3, pinkish, glabrous, lateral 2 adnate to 2 cm above corolla tube base, 1–2 mm long, middle one adnate to 1.8 cm above corolla tube base, ca. 1 mm long. Disc annular, ca. 0.5 mm high, yellowish. Pistil 2.5–3.5 cm long; ovary dark red, cylindrical, 1–1.5 cm long, ca. 0.5 mm in diameter, densely pubescent; style light green, ca. 1.5–2 cm long, densely pubescent and glandular-pubescent; stigma upper lobe lacking, lower lobe bifid, lobes ca. 1 mm long. Capsule linear, 2.5–3.5 cm long (excluding the persistent style), densely pubescent, splitting into 2 valves. Seeds small, ovoid to ellipsoid, 0.2–0.3× 0.1–0.2 mm.

Distribution, habitat and provisional conservation status: — Primulina longiflora is known only from the type locality in Nandan County, China. It grows on limestone rocks at elevations of 500– 670 m. We only found one small population with ca. 30 individuals, among which only ca. 15 are mature ones. Due to lack of time and inconvenient traffic, a thorough population assessment of this species in that limestone area has not been made, so it is best classified as ‘Data Deficient’ (DD) at present according to the IUCN Red List Categories and Criteria ( IUCN Standards and Petitions Committee 2024).

Phenology: —Flowering in June to October; fruiting in July to November.

Etymology: —The specific epithet is derived from the long corolla. The Chinese name is given as “ ẗẑffifffi ª ”.

Additional specimen examined (paratype): — CHINA. Guangxi Zhuang Autonomous Region: Nandan County, Baxu Xiang, cultivated in Guangzhou, 9 October 2024 (fr.), and vouchered as Y.H. Tong TYH-2906 (IBSC).

Discussion: — Primulina longiflora has high ornamental values due to its relatively small habit and conspicuous flowers. When noticing the unusual long and narrow corolla tube in Primulina , this new species also looks somewhat like three other species, viz. P. spiradiclioides Z. B. Xin & F. Wen in Xin et al. (2020: 245) from Guangxi, and P. silaniae X. X. Bai & F. Wen in Zhang et al. (2021: 125) and P. flexusa F. Wen, Tao Peng & B. Pan in Peng et al. (2020: 62) from neighboring province Guizhou, but all these three species have relatively short ovaries (<6 mm long) and capsules (<1.5 cm long), and very different morphology of leaves. Thus, there is little chance to confuse this new species with them. A distribution map of this new species and above mentioned morphologically similar species is provided ( Fig. 2 ).

Figures

FIGURE 1. Primulina longiflora. A. Plant in natural habitat; B. Flowering plant, top view; C. Plant in side view, showing the rhizomatous stem; D. Leaves, adaxial (left) and abaxial (right) surfaces; E. Flower, with long sigmoid tube in side view; F. Flower, front view; G. Calyx lobes; H. Opened corolla, showing adaxial surface and stamens; I. Stamens; J. Staminodes; K. Pistil with sepals removed; L. Bifid stigma. Scale bars: 2 cm (C, H); 1 cm (D, K); 5 mm (G, I); 3 mm (J, L). Photographed by Yi-Hua Tong.

FIGURE 2. A distribution map of Primulina longiflora and four morphologically similar species (P. curvituba, P. spiradiclioides, P. silaniae and P. flexusa).