Leptochilus phanerophlebius Liang Zhang, Zhen Long Liang & Zhi Yong Yu 2025, sp. nov.

Leptochilus phanerophlebius Liang Zhang, Zhen Long Liang & Zhi Yong Yu, sp. nov. (Fig. 1) Type:— CHINA. Yunnan: Jinping County, Mengla, Wengdangcun, elev. 950 m, 22°41’40.19” N / 102°54’34.05” E, on tree trunks in disturbed evergreen broad-leaved forests, 22 January 2024, Zhi-Yong Yu & Zong-Li Liang YZY-JL-002 (holotype KUN!; isotypes CDBI!, KUN!). Diagnosis:— Leptochilus phanerophlebius is most similar to L. brevipes in having a lanceolate sterile lamina and short petiole. However, L. phanerophlebius can be distinguished by its larger sterile lamina (21.5–51.3 × 4.1–6.7 cm) and more prominent venation, in contrast to the smaller sterile fronds of L. brevipes (22–34 × 2.1–2.6 cm) and its less distinct venation. Plants perennial, evergreen, epiphytic. Rhizomes long creeping, ca. 2–4 mm in diam., dorsiventrally flattened, scaled, with a few short phyllopodia and long roots. Apex of rhizome and basal part of petiole densely scaly; scales lanceolate, 0.9–1.7 × 0.3–0.6 mm, brown, basifixed, membranous, margins entire. Fronds dimorphic, sterile fronds the same length or shorter than fertile fronds. Sterile fronds ca. (20.7–) 30.4–52.5 cm long, laminae much longer than petioles; lamina simple, lanceolate to ovate-lanceolate, base attenuate, apex acuminate, margins undulate, ca. (19.5–)30.1– 51. 3 cm long, 4.8–6.1 cm wide at middle, thickly herbaceous, glabrous, adaxial surface dark green, abaxial surface light green; costae stramineous, distinct on both surfaces, grooved adaxially, obviously raised abaxially, a blackish band along adaxial costa, gradually narrow and obscure towards apex, widest portion of the band ca. 1–3 mm; stipes stramineous, ca. 0.7–1.6 mm in diam., 0.2–1.4 cm long; veins distinct, anastomosing, black, lateral veins 11–36 pairs, 0.4–1.6 cm apart, at angles of (50–)60°–85° with costae, slightly flexuous, ca. 0.5–1.6 mm from lamina margins; veinlets conspicuous, forming 3–4 irregular rows of areoles between costae and lamina margins, included free veinlets simple or forked, apex hydathodous. Fertile fronds linear, glabrous, grooved adaxially, ca. (21.3–)31.2–45.4(–61.2) cm long; lamina linear, gradually narrowed towards base, apex acuminate, 18.1–29.5(–46.3) cm long, 0.6–1.3 mm wide at middle; petiole stramineous, glabrous, ca. 7.9–16.2 cm long, 0.8–1.58 mm in diam. Sori acrostichoid. 2n = 72. Additional specimens examined (paratypes):—Same locality as holotype: 22 January 2024, Zhi-Yong Yu & Zong-Li Liang YZY-JL-003 (KUN!); 28 May 2023, Jin Zhao, Zong-Li Liang, Yong-Ling Qiu & Jian-Hong Li XLSJL-126 (KUN!, PYU!). Geographical distribution: —Currently, Leptochilus phanerophlebius is known only from the type locality in Jinping County, Yunnan province, China. However, the new species is likely to occur in similar rocky forest habitats in southeastern Yunnan and northern Vietnam. Ecology:— Leptochilus phanerophlebius was observed growing on small tree trunks within slightly disturbed forests at elevations between 940 m and 960 m. At the locality, a large population of approximately 200 individuals was documented. All observed individuals were growing on tree trunks, with creeping rhizomes extending to the base of tree trunks and their roots penetrating the soil. This growth habit aligns with the criteria for a hemiepiphytic species as defined by Zotz et al. (2021), referring to species that initially germinate on a host tree but later establish root contact with the soil. Etymology: —The species epithet phanerophlebius refers to the prominently visible venation on the sterile fronds. Its Chinese name is suggested as ẊṞAE唇″ (tu mai bao chun jue).