Primula yanbianensis T. Shuai, Lei Cai & Z. K. Wu, 2025

Shuai, Tian, Lin, Hong-qiang, Cai, Lei, Chen, Yu-fan & Wu, Zhi-kun, 2025, Primula yanbianensis (Primulaceae), a new species in Primula sect. Cortusoides from Sichuan, China, PhytoKeys 252, pp. 109-118 : 109-118

Primula yanbianensis T. Shuai, Lei Cai & Z. K. Wu sp. nov.

Diagnosis.

The new species is most similar to P. neurocalyx , P. longipilosa and P. sinomollis , sharing multicellular hairs covering the plant, subrounded leaf blade are more or less lobed, with distinct petiole and a deeply cordate base and campanulate or narrowly campanulate calyx. However, the new species is distinguished from the latter three mainly by its scape usually being lower than leaf clusters, umbel is in whorls of 1–2, broadly ovate bracts and rose to pink petals are distinctly veined (Figs 1 – 3 ). The main morphological distinctions between P. yanbianensis , P. neurocalyx , P. longipilosa and P. sinomollis are summarised in Table 1 .

Type.

China • Sichuan: Panzhihua City, Yanbian County, Yongxing Town . 27°4'32.95"N, 101°24'17.75"E, 1530 m alt., 28 June 2017 (fl.), Zhikun WU & Lei Cai, L. Cai 2017070; 15 July 2020 (fl.), Zhikun WU, ZKWu 2020053 (holotype: KUN!; Paratype: KUN!) .

Description.

A perennial herb with a short and usually inconspicuous rhizome and numerous robust fibrous roots, densely covered throughout with multicellular hairs. Leaves all rising from the root, forming a rosette, leaves including the petiole 10–25 cm long, petiole 5–18 cm, clothed with long spreading soft multicellular hairs, slightly sheathed at the base; leaf blade suborbicular to reniform, 4–12 cm long, 3–10 cm wide, apex obtuse, base cordate to deeply cordate, the leaf margin is undulate and lobed, the upper surface of the leaf sparsely septate hairs, while the lower surface covered with multicellular hairs along all the veins, mid-rib and 4, 5 pairs of pinnate lateral veins slightly impressed above, prominent below, reticulation open and rather feebly developed. Scapes 6–13 cm long, 1, 2 rising from the middle of the rosette leaves, shorter than leaves, densely covered with long soft multicellular hairs, carrying 1, 2 superposed umbels each with 3–5 flowers. Bracts broadly ovoid, 3–6 mm long, usually shorter than half of the pedicel, with long soft multicellular hairs. Pedicel 1, 2 cm, with a dense covering of long multicellular hairs. Flower heterostylous. Calyx narrowly campanulate to campanulate, 6–8 mm long, covered with long multicellular hairs abaxially, inner surface glabrous, cut to middle, lobes broadly ovate, with 3–5 prominent veins, apex with short cusp. Corolla rose to pink, tube 1.2–1.8 cm long, with long soft multicellular hairs outside, limb 1.5–2 cm in diameter, lobes obcordate, 6–8 mm in diameter, with prominent veins from yellow mouth, apex deeply emarginate. Pin flowers: tube 1.2–1.5 cm long, style 10–12 mm long, stamens at ca. 3 mm above the base of corolla tube; thrum flowers: tube 1.2–1.8 cm long, style 3–5 mm long, stamens at 2 / 3 length of corolla tube, ca. 10–12 mm above the base of corolla tube. Ovary globose (Figs 1 , 2 ). Capsule unknown.

Distribution and habitat.

This new species is currently only known from the type locality near Qingyi Road, Yongxing Town, Yanbian County, Panzhihua City, Sichuan Province, China and is mostly found on grassy slopes along the valley forest margin, at altitudes of 1500–1650 m (Fig. 1 ; Map 1 ).

Phenology.

Flowering occurs from June to July.

Etymology.

The specific epithet of the new species is taken from the Chinese Pinyin “ yanbian ”, the name of the county in south-western Sichuan, China, where the type specimen was collected (Map 1 ).

Vernacular name.

Chinese mandarin: yan bian bao chun (盐边报春).

Conservation status.

This new species is a rare species with a restricted distribution. Currently, only one population with less than 150 individuals has been found in the type locality. We have observed a steady decline in the territory area of the habitat due to road construction and grazing, based on the latter two field expeditions conducted in 2020 and 2024. Therefore, in combination with the information currently available and in accordance with the guidelines for the use of the IUCN Red List Categories and Criteria ( IUCN 2024), the conservation status of this new species has been assessed as ‘ Critically Endangered’ (CR B 1 ab (i, iii )).

Additional specimens examined

(paratypes). • The same locality as holotype, 18 June 2024, Tian Shuai, TSh 2024045 ( KUN!) .

Figures

Figure 1. Primula yanbianensis sp. nov. A habitat B habit in flowering C fresh plant with roots D inflorescence E leaves, left: upper surface, right: lower surface F bracts and calyx G calyx and stamens H flower, front view I pin flower and thrum flower. Photographed by Z. K. Wu.

Map 1. Location of the distribution of Primula yanbianensis in Yanbian County, Sichuan.

Figure 2. Primula yanbianensis sp. nov. A habit B leaves, left: upper surface, right: lower surface C flower, left: thrum flower, right: pin flower D calyx and stigma E calyx and ovary. Drawn by Ms. Xiang-Li Wu.

Figure 3. Primula yanbianensis and three of its allies A holotype of P. yanbianensis (L. Cai 2017070, KUN!) B holotype of P. longipilosa (Gengma TCM Resources Survey Exped. 5309260482, KUN!) C type of P. neurocalyx (P. G. Farges 1369, P!) D syntype of P. sinomollis (Forrest, G. 5523, E!) E P. yanbianensis F P. longipilosa G P. neurocalyx H P. sinomollis. E, G, H photographed by Z. K. Wu from their type locality, F photographed by Li Chen from its type locality.