Primulina xingyiensis X. X. Bai & F. Wen, 2025

Gu, Jiang-Miao, He, Song-Tao, Wen, Fang, Bai, Xin-Xiang & Li, Mei-Jun, 2025, Primulina xingyiensis (Gesneriaceae), a new species in the karst landforms of Guizhou Province, China, PhytoKeys 251, pp. 1-12 : 1-12

Primulina xingyiensis X. X. Bai & F. Wen sp. nov.

Figs 2 , 3

Type.

CHINA • Guizhou: Xingyi City, Jingnan Town , growing on rock walls in limestone caves, 24°56'N, 104°53'E, elev. ca. 877 m, 6 July 2022, X. X. Bai et al. XYS 07277 (holotype: GZAC!; isotype: IBK!) .

Diagnosis.

The corolla morphology of Primulina xingyiensis is similar to that of P. davidioides , and the phylogenetic tree shows that its closest relative is P. malingheensis , but there are also clear differences in morphological characteristics between the three (Table 2 , Fig. 4 ). Primulina xingyiensis can be distinguished from P. davidioides by the thinner and smaller leaves, slightly fleshy (vs. pachyphyllous, rigid and coriaceous when dry); the shorter peduncles, 0.5–4 cm long only [vs. 5–9 (– 12) cm long]; the fewer flowers, 1–6 flowers per cymes (vs. 5–9 (– 11) flowers per cymes); the smaller corolla, ca. 5 cm long (vs. ca. 6 cm long); the staminodes glabrous, central one ca. 1 mm long (vs. sparsely glandular-puberulous, central one ca. 4.5 mm long); the ovary shorter than style (vs. the ovary longer than style). Primulina xingyiensis can be distinguished from P. malingheensis by the larger leaves, 4.3–9.8 × 3.1–5.1 cm (vs. 1.7–5.8 × 1.2–3 cm); the larger bracts, 2.0–4.3 × 1.5–2 cm, white when flowering, apex margin light green, occasionally purplish-red (vs. 1.3–1.8 × 0.8–1.0 cm, pale green to brownish-purple); the white calyx lobes (vs. light purple about 1 / 2 way down from top, yellowish green below); a dark purple spot between adaxial lip lobes (vs. throat roof with a reddish-brown spot); the pale yellow anthers (vs. white anthers, ventral surface slightly bluish purple).

Description.

Perennial herb. Rhizome subcylindrical, 5–16 mm long, 1.3–2 mm in diameter. Leaves all basal, 4 to 12, opposite; petiole 0.5–3.8 cm long, 1–3 mm in diameter, densely white pubescent; leaf blade slightly fleshy, ovate or oblong, (1.3 –) 4.3–9.8 × (0.7 –) 3.1–5.1 cm, margin irregular shallow dentate, puberulent on both sides, base cuneate, apex obtuse or suborbicular; midrib adaxially slightly impressed, abaxially prominent, lateral veins 2–5 on each side. Cymes 1–3 on each plant, 1–6 flowers per cymes; peduncle 0.5–4 cm long, ca. 2 mm in diameter, densely white pubescent. Bracts 2, opposite, narrowly ovate to suborbicular, white when flowering, apex margin light green, occasionally purplish-red, 2.0–4.3 × 1.5–2 cm, outside densely pubescent, inside sparsely pubescent, margin serrate from above the middle, base slightly truncate, apex acuminate; pedicels 5–9 mm long, ca. 1.5 mm in diameter, densely covered by short glandular hairs; calyx 5 - lobed to base, lobes nearly equal in length, white, linear-lanceolate to lanceolate, 5–8 mm × 1.5–2.2 mm, outside with short glandular hairs, inside glabrous, margin entire, apex acuminate. Corolla purple, 4.98–5.26 cm long, outside with glandular hairs, inside with vertical purple stripes, sparsely short glandular hairs below the insertion of the filaments; tube infundibuliform, 3.65–3.82 cm long, 1.14–1.27 cm diameter at mouth, 4.7–5.1 mm in diameter at base; limb distinctly 2 - lobed, adaxial lip 2 - parted to near base, dark purple spot between lobes, lobes semi-elliptic, ca. 6 × 6 mm; abaxial lip ca. 1.8 cm long, 3 - lobed to near middle, lobes oblong, 8–10 × ca. 6 mm. Stamens 2, inserted at 2.3 cm from the base of the corolla; filaments linear, 0.96–1.12 cm long, sparsely covered by short glandular hairs, distinctly geniculate, white, pale yellow basally or below the middle; anthers 2.9–3.2 mm long, 1.44–1.56 mm across, light yellow, reniform, fused by their adaxial surfaces, abaxial surfaces sparsely white bearded. Staminodes 3, glabrous, white, lateral ones ca. 4 mm long, inserted at 1.5 cm from the base of the corolla, central one ca. 1 mm long, inserted at 9 mm from the base of the corolla. Disc ca. 1 mm high, light yellow, annular, glabrous. Pistil 3.58–3.65 cm long, white, densely covered by white short glandular hairs, ovary linear, 1.54–1.61 cm long, 1.47–1.51 mm in diameter, densely covered by short glandular hairs; style linear, ca. 2 cm long, stigma 4.92–5.04 mm long, only with abaxial lip, oblique trapeziform, apex 2 - lobed, lobes triangular. Capsule linear, 2.4–3.3 cm long.

Phenology.

Flowering from June to July and fruiting from August to November.

Etymology.

The specific epithet ‘ xinyiensis ’ refers to the type locality Xingyi. Its Chinese name is Xīng Yì Bào Chūn Jù Tái (兴义报春苣苔).

Distribution and habitat.

This new species is currently distributed only in the type locality of Xingyi City, Guizhou Province, China, where two populations have been found, both growing on limestone cave walls. Accompanying species mainly include Petrocosmea sp. , Adiantum capillus-veneris L., and Aleuritopteris anceps (Blanf.) Panigrahi.

Conservation status.

Currently, only two populations of Primulina xingyiensis have been found in Xingyi City, Guizhou Province, with a straight-line distance of less than 10 km. The number of mature individuals in the two populations is about 500, and they are close to human settlements, making them susceptible to anthropogenic disturbances. We have not found the species again in similar habitats during extensive investigations in the adjacent areas. Since the estimated number of mature individuals is about 500, the new species should be assessed as ‘ vulnerable’ (VU) according to criterion D 1 of the IUCN Red List Categories and Criteria ( IUCN 2022).

Additional specimens examined.

Primulina malingheensis , China • Guizhou Province, Xingyi City, Maling River , 25°3'N, 104°59'E, ca. 877 m a. s. l., 18 May 2022, X. X. Bai & Y. L. Zhou MLHXG 202205187 (holotype: GZAC!) .

Notes.

The sequences of Primulina malingheensis _ 1 used in this study were uploaded into the GenBank database and labeled as P. secundiflora (Chun) Mich. Möller & A. Weber by Kong et al. (2017). At that time, researchers generally identified a plant collected in Xingyi City, Guizhou Province, China, as P. secundiflora . Later, our research team conducted a field survey of this species and found that it was significantly different from P. secundiflora and from other formally published species of Primulina , and we published it as a new taxonomic unit and named it P. malingheensis ( Zhou et al. 2023) . In this study, we obtained the sequences of the type locality of P. malingheensis , labeled as P. malingheensis _ 2. Primulina malingheensis _ 1 and P. malingheensis _ 2 formed a fully supported clade in the phylogenetic tree (Fig. 1 ), and the rpl 32 - trn L, trn L- trn F, atp B- rbc L, and ITS sequences of P. malingheensis _ 1 and P. malingheensis _ 2 were only present at two, zero, one, and six variant sites. The sequences of P. secundiflora uploaded by Kong et al. (2017) actually misidentified P. malingheensis as P. secundiflora , so it is labeled as P. malingheensis _ 1 in this study.

Figures

Figure 1. The partial ML and BI phylogenetic trees (red part) from the analyses of the combined dataset of the rpl 32 - trn L, trn L- trn F, atp B- rbc L, and ITS sequences. Numbers above branches are ML ultrafast bootstrap values; numbers below branches are BI posterior probability values. The green background indicates two populations of the new species.

Figure 2. Primulina xingyiensis A plant B leaves C corolla D bracts E calyx lobes F corolla opened showing internal features G pistil and disc H stigma I stamens (Drawn by Bai-Qiu He).

Figure 3. Primulina xingyiensis A habitat B plant C leaves D, E inflorescence F bracts G calyx lobes H front view of the corolla I corolla opened showing internal features J anthers K stamens L pistil and disc M fruits (Photographed by Xin-Xiang Bai).

Figure 4. Primulina xingyiensis, P. malingheensis and P. davidioides A P. xingyiensis of Jingnan Town B P. xingyiensis of Wanfenglin C P. malingheensis D P. davidioides A- 1, B- 1, C- 1, D- 1 Plant with flowering A- 2, B- 2, C- 2, D- 2 Cymes A- 3, B- 3, C- 3, D- 3 Floral anatomy, staminode indumentum (inset) (D- 1 provided by Dr. Fang Wen; D- 2 provided by Mr. Tao-Ran Chen; D- 3 provided by Mr. De-Chang Meng).