Taxonomic treatment

Primula exserta

Lei Cai, Gui L.Zhang & Z.K.Wu sp. nov.

3E748DE0-E16E-565F-8A42-F94B8C8F5D26

urn:lsid:ipni.org:names:77394089-1

Figs 1, 2, Fig. 3: A1, A2

Diagnosis.

This new species is most similar to P. membranifolia, P. pengzhouensis, and P. mianyangensis within the same section, all of which share the following characteristics: aboveground parts farinose, calyx campanulate or narrowly campanulate, and leaves obovate or sub-spatulate. However, it is distinguished from the three species mentioned above by the following morphological features: petiole with broad wings, 7–8-lobed corolla and calyx, corresponding 7–8 stamens, floral type uniform: stamens of all flowers inserted at the middle of the corolla tube, free from the tube at the mouth, extending ca. 5 mm beyond the tube, style 2.5–3 cm long, longer than the stamens (Figs 1, 2). A comparison of plant photographs of P. exserta with P. membranifolia, P. pengzhouensis, and P. mianyangensis is provided in Fig. 3, and the main morphological differences are summarized in Table 1.

Figure 1.: Primula exserta sp. nov. A. Habitat; B. Habit during flowering; C. Lateral view of the plant; D. Leaves, left: upper surface, right: lower surface; E. Flower, frontal view; F. Flower, lateral view; G. Dissected corolla showing the anthers and stigmas; H. Dissected corolla with the ovary; I. Dissected calyx.

Figure 2.: Primula exserta sp. nov. A. Flowering habit; B. Leaves, left: upper surface, right: lower surface; C. Flower, lateral view; D. Dissected corolla showing the anthers and stigmas; E. Dissected calyx. Drawn by Ms. Yang-yang Zheng.

Figure 3.: Primula exserta sp. nov. and three morphologically similar taxa in Primula sect. Aleuritia. A1, A2. P. exserta; B1, B2. P. membranifolia (Dali, Yunnan, type locality); C1, C2. P. pengzhouensis (Pengzhou, Sichuan, type locality); D1, D2. P. mianyangensis (Mianyang, Sichuan, type locality).

Characters | P. exserta | P. membranifolia | P. pengzhouensis | P. mianyangensis
Leaves blade | Obovate; apex subrounded; margin densely serrate, occasionally doubly serrate | Elliptic; apex rounded; margin serrate, with obtuse or slightly acute teeth | Elliptic; apex broadly obtuse to subrounded; margin serrate-dentate | Elliptic; apex obtuse to more or less acute; margin dentate-serrate from the lower 1/3
Petiole | Broadly winged, nearly as long as the leaf blade | Narrowly winged, 1/2 as long as the leaf blade, rarely nearly as long as the leaf blade | Narrowly winged; inner leaves: petiole 1/3–1/2 as long as the leaf blade; outer leaves: petiole usually as long as the leaf blade | Unwinged; inner leaves: petiole almost as long as the leaf blade; outer leaves: petiole approximately twice as long as the leaf blade
Scapes | Almost invisible | (1–)2–5 cm tall | At most 2 mm tall | Almost invisible
Flower | Monomorphic; filaments and style conspicuously exserted from the corolla tube and longer than the corolla lobes | Distyly, anthers and filaments all included within the corolla tube | Distyly, anthers and filaments all included within the corolla tube | Distyly, anthers and filaments all included within the corolla tube
Calyx | Narrowly campanulate, 3–5 mm long, 7–8-lobed, divided nearly to base | Campanulate, 3–4 mm long, 5-lobed, divided to or slightly beyond the middle | Narrowly campanulate, 5–7 mm long, 5-lobed, parted slightly beyond middle | Narrowly campanulate, 8–9 mm long, 5-lobed, split to 2/3 of its length
Corolla | Pale purple or pink; 7–8-lobed, oblong, apex entire or irregularly divided | Pale purplish red; 5-lobed, obovate, apex deeply emarginate | Rose or pale purple, exannulate; 5-lobed, obovate, deeply emarginate | Pale rose-purple; 5-lobed, obovate, bilobed, lobules entire

Type.

China • Yunnan: Hekou County, Lianhuatan Township, Zhonglinggang Village, Wanzhangya; 22°55'00"N, 103°39'57"E, 1700 m alt.; 22 May 2026 (fl.); Lei Cai and Guiliang Zhang CL26052201 (holotype: KUN!; isotypes: KUN!).

Description.

Perennial herb. Aboveground parts, except petals farinose; entire plant glabrous. Rhizome short and thick, bearing numerous fleshy roots and fibrous rootlets. Leaves rosette somewhat compact, arising from the apex of a greatly shortened rhizome, with withered leaves from the previous year remaining at the base; leaf blade obovate, oblanceolate, or sub-spatulate, 1–3 cm long, 0.5–1.5 cm wide, apex subrounded, base gradually attenuate into a wide winged petiole, margin densely serrate, occasionally doubly serrate, membranous when dry, upper leaf surface slightly farinose, lower leaf surface covered with easily deciduous yellow farina; midvein slightly broad, lateral veins slender and prominent on the lower surface; petiole approximately as long as the leaf blade. Scapes greatly shortened, almost inconspicuous. Flowers 2–4, borne within the leaf rosette. Pedicel almost inconspicuous, with a linear bract 2–3 mm long at the base. Calyx cup-shaped, 3–5 mm long, 7–8-lobed, lobes divided nearly to the base, both inner and outer surfaces heavily covered with yellow farina; lobes narrowly lanceolate, apex acute or acuminate. Flowers monomorphic. Corolla campanulate, pale purple or pink, throat without an annulus; corolla limb 1.2–1.8 cm in diameter, lobes 7–8, oblong, apex entire or irregularly divided. Corolla tube slender, 1.2–1.5 cm long, externally covered with fine yellow farina; all flowers with 7–8 stamens inserted at the middle of the corolla tube, free from the tube at the mouth, extending ca. 5 mm beyond the tube; style 2.5–3 cm long, longer than the stamens, ovary ovoid, ca. 1 mm long at anthesis. Capsule unknown.

Distribution and habitat.

This new species is currently known from two populations in Zhonglinggang Village, Lianhuatan Township, Hekou County, and Dimi Village, Xinxian Township, Pingbian County, Yunnan Province, China. It is mainly distributed on dry cliffs at elevations between 1700 and 2000 m (Fig. 1; Map 1).

Map 1.: Distribution of P. exserta in Hekou and Pingbian, Yunnan.

Phenology.

The species was observed to flower from April to the end of May.

Etymology.

The specific epithet exserta is derived from the Latin exsertus, meaning “protruding” or “extended outward,” alluding to the style and stamens that are distinctly exserted beyond the mouth of the corolla tube, a key diagnostic character distinguishing this species from its congeners in P. sect. Aleuritia.

Vernacular name.

Simplified Chinese: 大围山报春; Chinese Mandarin: “dà wéi shān bào chūn.”

Additional specimen examine.

China • Yunnan: Pingbian County, Xinxian Township, Dimi Village, Qiche. 23°2'30"N, 103°31'32"E, 1996 m alt.,20 April 2021 (fl.), Lei Cai and Guiliang Zhang CL21042001 (KUN!).

Provisional conservation status.

Since this species was discovered in 2021, only two populations have been found within the Daweishan National Nature Reserve, each consisting of approximately 100 adult individuals. These two localities are in Pingbian County and Hekou County and are separated by a relatively short linear distance. Potential populations may still exist in the surrounding areas. Until further investigations are conducted, the conservation status of this species is assessed as “Data Deficient” (DD) in accordance with the IUCN Red List Criteria.