Petrocosmea pengzhouensis K. Huang & Z. X. Fu 2025, sp. nov.

Petrocosmea pengzhouensis K. Huang & Z. X. Fu sp. nov. Type. China • Sichuan Province, Chengdu City, Pengzhou, Feilaifeng Scenic Area of Sichuan Longmen Mountain National Geological Park, 31. 31.193542, 103.917283, ca. 1116 m, 30 April 2025, Ke Huang & Zhixi Fu 8560 (holotype: SCNU!; isotype: SCNU!) (Figs 1 – 4). Diagnosis. In terms of traits such as being a rosette-forming herb, possessing a single-flowered cyme, and having a pale purple corolla, P. pengzhouensis most closely resembles P. duclouxii but differs primarily in the following characteristics: leaf shape (ovate to oblique-ovate vs. ovate to nearly orbicular), corolla throat (spotless vs. bearing two deep purple spots), and filament pubescence (translucent-puberulent vs. rust-brown puberulent) (Table 2). Description. Perennial rosette-forming herbs. Roots fibrous, clustered. Leaves herbaceous, 13–26, basal, densely rosulate; inner leaves subsessile or with petioles to 2.2 cm long in outer leaves, densely pubescent and sparsely villous; leaf blade 0.4–1.8 cm long, 0.3–1.2 cm wide, ovate to oblique-ovate in outer leaves, apex obtuse to rounded, base cordate (sometimes oblique), margin crenate, adaxially sparsely villous, abaxially densely pubescent or sparsely villous; lateral veins 3–4 per side, slightly raised or flat abaxially. Cymes 1–5, each 1 - flowered; peduncle 0.5–4.3 cm long, densely pubescent or sparsely villous. Bracts absent. Calyx zygomorphic, 5 - parted to base; lobes narrowly lanceolate, 1.9–2.7 mm long, externally pubescent. Flowers pale purple, 8.7–13.8 mm long; corolla externally densely puberulent, internally glabrous; tube 4.3–6.4 mm long, throat 4–5 mm in diameter, base 2.5–3 mm in diameter, subcampanulate, throat blue-purple, unspotted; adaxial lip conspicuously shorter, 8–9 mm long, 2 - lobed to the middle, lobes ovate, 2–2.3 mm long, 2–2.5 mm wide, slightly reflexed; abaxial lip 11–13.8 mm long, 3 - lobed to the middle, lobes long-ovate, 2.6–3.0 mm long, 3.6–4.2 mm wide, slightly reflexed. Stamens 2, ca. 2.5 mm long; filaments adnate, ca. 1 mm above corolla base, 1.8–2.3 mm long, 0.3–0.5 mm in diameter, densely translucent-puberulent; anthers ovate, dehiscing longitudinally, ca. 1 mm long, 1.0– 1.1 mm wide; thecae 2, parallel. Pistil 4.3–5.4 mm long; ovary densely villous, ovoid, ca. 1.3 mm long, 1.2–1.5 mm in diameter; style 3–4.1 mm long, 0.3 mm in diameter, sparsely pubescent below middle-upper portion, slightly geniculate (ca. 45 °) above base; stigma capitate, ca. 0.4 mm in diameter. Capsule straight relative to pedicel, 2.9–3.5 mm long, 1.2–1.3 mm in diameter, oblong to ovoid, dehiscing loculicidally to base. Phenology. Flowering from April to May, fruiting in the wild is unknown; only capsules of the previous year were observed. Etymology. The new taxon is named after the type locality, Pengzhou, Chengdu City, China. Vernacular name. The Chinese name is “ péng zhōu shí hú dié ” (彭州石蝴蝶). Distribution and habitat. To date, only a single population has been found, exclusively in the Feilaifeng Scenic Area of the Longmen Mountain National Geological Park in Pengzhou, Chengdu City, Sichuan Province, China. Petrocosmea pengzhouensis was found growing on rocks in limestone caves at an elevation of ca. 1116 m (Fig. 5). Conservation status and IUCN Red List category. In the type locality, a population of approximately 100 mature individuals was discovered. This habitat is located within the local Feilaifeng Scenic Area, and it is highly likely that additional populations exist in the region. Before further investigations, this species should be assessed as “ Data Deficient ” (DD) according to the IUCN standards (IUCN 2024).