Petrocosmea miechangensis Sheng H. Tang & Cong R. Li, 2025

Petrocosmea miechangensis Sheng H. Tang & Cong R. Li sp. nov.

Figs 1 View Figure 1 , 2 View Figure 2

Diagnosis.

The new species displays the following characteristics: the corolla tube is shorter than the limb, and the adaxial corolla lip is significantly shorter than the abaxial corolla lip. Consequently, it should be classified within sect. Minor Z. J. Qiu within the genus Petrocosmea . Species in sect. Minor Z. J. Qiu typically exhibit minor variations in their flowers, fruits and seeds, but they display significant differences in their leaves and hairs. P. miechangensis and P. sericea are found in Wenshan City, Yunnan Province, China and they both possess similar leaf blade hairs (the silvery-white, glossy, silk-like hairs are unique to the genus Petrocosmea ). So P. miechangensis is most similar to P. sericea (Fig. 3 View Figure 3 ). However, it diverges in several critical respects: it flowers from April to May, not in October, and the stamens and pistil form a triangular interspace (vs. a crescent-shaped one). Additionally, it features very densely appressed pilose ( 1.3–1.5 mm long) leaf blades on the underside (vs. densely appressed pubescent, 0.7–1 mm long), spreading pilose and glandular puberulent calyx lobes (vs. densely appressed pubescent), spreading pilose and glandular puberulent pedicels (vs. densely appressed sericeous pubescent), and filaments that are glandular puberulent and densely glandular pubescent (vs. densely puberulent), with a bend of roughly 90 degrees (vs. roughly 30 degrees).

Type.

China • Yunnan Province: Maguan County, Miechang Town , 22°51'N, 104°03'E, ca. 1,400 m, 19 May 2025, Sheng H. Tang & Da-Zhu Tang 202505002 ( holotype: CSH! [accession number CSH 0220071 View Materials ]; isotype: the Guizhou Botanical Garden!) GoogleMaps .

Description.

Perennial herbs. Rhizome short, 5–8 mm long, 4–5 mm in diameter. Leaves all in basal rosette, 15–60; inner leaves with petioles 0.5–7.5 mm long or absent, outer leaves with petioles 7.5–62 mm long, 0.8–1.3 mm in diameter, densely descending appressed pubescent and sparsely spreading villous; leaf blade papery when dry, ovate or elliptic, 8.2–20 × 4.3–12.5 mm, adaxially densely appressed pubescent, abaxially very densely appressed sericeous pilose ( 1.3–1.5 mm long), base cuneate or broadly cuneate, margin entire and sparsely spreading villous, sometimes shallowly crenate, apex acute or acuminate; lateral veins 2–3 on either side of midrib, adaxially and abaxially inconspicuous. Cymes 1–8, one flower per cyme; peduncle 14–24 mm long, 0.9–1.2 mm in diameter, spreading pilose and glandular puberulent; bracts 2 or 3, lanceolate, nearly equal, 1.6–2.9 × 0.3–0.5 mm, sparsely pubescent outside, glabrous inside; pedicels 8–16 mm long, spreading pilose and glandular puberulent. Calyx zygomorphic, spreading pilose and glandular puberulent outside, glabrous inside; adaxial calyx lip 3 - parted nearly to base, abaxial calyx lip 2 - parted to base, all segments nearly equal, lanceolate, 3.7–4.7 × 0.8–1 mm, margin entire, apex acuminate. Corolla blue-purple, 14.5–17 mm long, puberulent outside, glabrous inside; tube 3.8–4.7 mm long, 4.4–6 mm in diameter at mouth, 3–3.8 mm in diameter at base, broadly tubular, two dark blue-purple stripes inside tube beneath anthers; throat blue-purple, without stripes or with two inconspicuous stripes; limb distinctly 2 - lipped, adaxial corolla lip 3.4–4.5 mm long, narrowly triangle, bent and keeled, apex emarginate, margin recurved, abaxial corolla lip 9.8–13.1 × 13.8–18.4 mm, broadly obovate, 3 - parted to near middle, segments subequal, ovate, 4–6.7 × 5–7.5 mm. Stamens 2, connivent, adnate to corolla tube near base, included; filaments 2.6–3 mm long, with a bend of roughly 90 degrees, glandular puberulent, and adaxially densely glandular pubescent near middle; anthers coherent, ovate, 1.7–1.9 × 1.2–1.4 mm, basifixed, sparsely glandular puberulent on dorsal side; thecae two, parallel, not confluent, poricidal near apex. Staminodes three, included, adnate to corolla tube near base, 0.9–1.4 mm long, glabrous. Disc absent. Pistil 9–10.8 mm long; ovary densely appressed pubescent, narrowly ovoid or oblong, 1.1–2.2 mm long, 0.8–1.1 mm in diameter; style 7.9–8.6 mm long, sparsely glandular puberulent, and appressed pubescent near base; stigma nearly globose, ca. 0.3 mm in diameter, apex rounded. Capsule straight in relation to pedicel, 5–8 mm long, ca. 1.5 mm in diameter, oblong, glabrous, dehiscing loculicidally to base; valves 2, straight, not twisted. Seeds 0.4–0.6 mm long, ellipsoid, unappendaged.

Phenology.

Flowering occurs from April to May, fruiting in the wild is unknown. Only capsules of the previous year were observed.

Etymology.

The new taxon was named after its locality, Miechang Town, Maguan County, China.

Vernacular name.

The Chinese name is “Miè Chăng Shí Hú Dié” (篾厂石蝴蝶).

Distribution and habitat.

Two populations have been discovered in Miechang Town, Maguan County, China (Fig. 4 View Figure 4 ). The plants thrive on moist, shady cliffs and limestone surfaces. The primary companion species are Thalictrum ichangense Lecoy. ex Oliv. ( Ranunculaceae ), Oreocharis hekouensis (Y. M. Shui & W. H. Chen) Mich. Möller & A. Weber ( Gesneriaceae ), Anna mollifolia (W. T. Wang) W. T. Wang & K. Y. Pan ( Gesneriaceae ), Impatiens wenshanensis S. H. Huang ( Balsaminaceae ), and Clarkella nana (Edgew.) Hook. f. ( Rubiaceae ).

Conservation status.

Two populations, totaling approximately 150 mature individuals, were discovered in Miechang Town, Maguan County, China. The straight-line distance between the populations is approximately 2 kilometers. Road construction could pose a potential threat to their survival. It is highly probable that additional populations exist in this region. Until further investigation is carried out, the species should be classified as “ Data Deficient ” (DD) following IUCN standards ( IUCN 2024).

Taxonomic notes.

Petrocosmea miechangensis bears resemblance to 23 species and one variety of Petrocosmea , sharing the following characteristics: the corolla tube is shorter than the limb, the adaxial corolla lip is significantly shorter than the abaxial corolla lip, and the adaxial corolla lip apex is emarginate. An identification key for P. miechangensis and its related species is presented.

Key to Petrocosmea miechangensis and its related species