Primula jiangyouensis J. L. Gu & Z. K. Wu, 2025

Gu, Jiu-lin, Wang, Hua-dong, Lin, Hong-qiang, Jiang, Xiao-qi, Shuai, Tian & Wu, Zhi-kun, 2025, Primula jiangyouensis (Primulaceae), a new species of Primula sect. Auganthus from Sichuan, China, PhytoKeys 260, pp. 25-35 : 25-35

Primula jiangyouensis J. L. Gu & Z. K. Wu sp. nov.

Diagnosis.

The new species is most similar to P. sinensis , P. rupestris , and P. xingshanensis , sharing hairs that covered the leaves and stems, lobed leaf blade, distinctly petiole and distinctively broad and flat-bottomed calyx. However, the new species is distinguished from the latter three mainly by its branched and stout rhizomes usually up to 40 cm, yellow corollas with a distinct fan-shaped reddish-brown blotch at the base of lobes, and short glandular hair on aboveground parts (Figs 1 – 4 ). The main morphological distinctions between P. jiangyouensis , P. sinensis , P. rupestris , and P. xingshanensis are summarized in Table 1 .

Type.

China • Sichuan: Mianyang, Jiangyou County, Yongshen town, Jingtai village . 32°0'31"N, 104°53'26"E, 1070 m alt., 12 November 2022 (fl.), Jiulin Gu, GJL 384 (holotype: KUN!; isotype: KUN!) .

Description.

Perennial herb, the entire aboveground parts densely covered with short glandular hairs; roots purplish-brown and pale purple, few in number, fibrous and brittle; rhizome woody, stout and elongated, up to 40 cm long and 1 cm thick, usually with 2–8 branches, bearing numerous persistent dry leaf sheath from base to apex. Leaves mostly clustered at the apex of the rhizome, rosette, including petiole 8–24 cm long; petiole 4–16 cm long, densely covered with short glandular hairs, base expanded, pale red or green, brittle when fresh; leaf blade oblong-ovate to ovate-orbicular, 4–8 cm long, 2–6 cm wide, apex obtuse-rounded, base truncate and oblique, margin pinnately 4–6 - lobed, parted up to 1 / 2 or more of the blade, lobes oblong, each side with 3–12 obtuse notched teeth, slightly thick when fresh, papery when dry, mid-rib prominent, lateral veins 5–7 pairs, slightly concave adaxially and densely covered with short glandular hairs, raised abaxially and densely glandular-hairy along veins. Scape 5–35 cm tall, green; umbels 1–5 - whorled, each whorl with 2–11 flowers. Bracts lanceolate, entire, 5–10 mm long, acute at apex, glandular-hairy. Pedicels 2–6 cm long, glandular-hairy. Calyx 6–9 mm long, base inflated and hemispherical, 4–6 mm in diameter, enlarging in fruit to 8–12 mm in diameter, mostly 5 - lobed (rarely 4 or 6), cut up to half its length, lobes triangular, densely glandular-hairy on both surfaces. Corolla yellow, glandular-hairy outside, limb 1.5–3.2 cm in diameter, throat yellow, without an annular appendage; lobes broadly obovate, apex bifid, margin entire or lacerate, with a fan-shaped reddish-brown blotch at the base. Flower heterostylous, Pin flowers: corolla tube 14–19 mm long, stamens inserted near the middle of the tube, style 10–18 mm long, nearly reaching or slightly exceeding the throat; thrum flowers: corolla tube 15–19 mm long, stamens inserted 10–15 mm from base of corolla tube, style 4–7 mm long. Capsule ovoid, 5–10 mm in diameter, shorter than the calyx. Seeds globose or ovoid, about 1.0 mm in diameter, finely vesicular-surfaced.

Distribution and habitat.

The new species is currently known from the type locality near Jingtai village, Cangwangzhai Scenic Area, Yongshen town, Jiangyou County, Sichuan Province, China, and is mostly found on shady ledges of limestone cliffs, at an altitude of 1070–1550 m (Fig. 1 , Map 1 ).

Phenology.

The species was observed to flower from November to February of the following year, fruiting from March to April.

Etymology.

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

Vernacular name.

Chinese mandarin: jiang you bao chun (江油报春).

Provisional conservation status.

This species exhibits a highly restricted distribution range, currently documented solely from the type locality within the Cangwangzhai Scenic Area. Field investigations have identified three spatially proximate but ecologically isolated subpopulations occupying distinct microhabitats. These subpopulations occur on fragmented shady limestone cliffs at varying elevations (ranging from 1070 to 1550 m a. s. l.). Population viability analysis indicates that the total number of mature individuals across all subpopulations is critically less than 250. Longitudinal monitoring data (December 2023 and April 2024) reveal progressive contraction in the area of occupancy (AOO) and continuing degradation of habitat quality. The principal threatening processes include: (1) climate change-induced alteration of microclimatic conditions (2) accelerated habitat fragmentation from geological processes; (3) edge effects exacerbating population isolation. Applying the IUCN Red List Categories and Criteria (Version 16.0, 2024), our assessment demonstrates that P. jiangyouensis meets the threshold for Critically Endangered (CR) status under criterion B 1 ab (i, ii, iii), based on: extent of occurrence (EOO) <100 km 2 (B 1), severely fragmented habitat (a), with continuing decline (b) in extent of occurrence (i), area of occupancy (ii) and area, extent and / or quality of habitat (iii).

Additional specimens examined

(paratypes). The same locality as holotype, 21 November 2022, Jiulin Gu & Huadong Wang, GJL 385 ( KUN!) ; 28 December 2023, Zhikun Wu, ZKWu 2023305 ( KUN!) , 27 April 2024, Zhikun Wu, ZKWu 2024060 ( KUN!) .

Figures

Figure 1. Primula jiangyouensis sp. nov. A. Habitat; B, C. Flowering plants; D. Plant with roots and rhizomes; E. Leaves, left: upper surface, right: lower surface; F. Infructescences; G. Bracts and pedicels; H. Flower, lateral view; I. Longitudinal section of pin flower (left) and thrum flower (right); J. Calyx and young fruit; K. Longitudinal section of ovary; L. Ripe seed. Photographed by J. L. Gu and Z. K. Wu.

Map 1. Location of the distribution of Primula jiangyouensis in Jiangyou, Sichuan.

Figure 4. Type specimens of Primula jiangyouensis and three of its allies. A. Holotype of P. jiangyouensis (GJL 384, KUN!); B. Holotype of P. rupestris (Farrer 734, E!); C. Holotype of P. xingshanensis (YCMY 152, IBSC!); D. Lectotype of P. sinensis (BM barcode BM 000996827); E. Type of P. filchnerae (photo, Filchner 37, E 00024341).