Leptochilus kachinensis Liang Zhang & Li Bing Zhang

Zhang, Liang, Lu, Ngan Thi, Zhou, Xin-Mao, Zhou, Zhuo, Thepkayson, Khamphanh, Luong, Thien Tam & Zhang, Li-Bing, 2024, Exploring the diversity of the Java fern genus Leptochilus (Polypodiaceae) in the Indo-Burma Biodiversity Hotspot, Phytotaxa 659 (3), pp. 213-235 : 220-221

3. Leptochilus kachinensis Liang Zhang & Li Bing Zhang , sp. nov. ( Fig. 5 ).

Type: MYANMAR. Kachin State: Putero District, Putao Town, Hpaw Wang Daru, N of Sum Pi Yang, 380 m, 26.90°N / 97.70°E, on the tree trunk, 12 April 2009, Yun-Fei Deng, Chang-Chun Ding & Lin-Fang Wu, Irrawaddy Expedition No. 3200 (holotype CDBI-0193822!).

Diagnosis: Leptochilus kachinensis is distinguished by its dimorphic fronds, fertile fronds nearly the same length as sterile fronds, sterile laminae lanceolate, up to 39 cm long, thinly chartaceous, and venation distinct on both sides of lamina.

Plants perennial, evergreen, epiphytic. Rhizome long creeping, robust, ca. 3.5–6.1 mm in diam., dorsiventrally flattened, with a few short phyllopodia and roots, sparsely scaly, scales lanceolate, 1.9–4.5 × 0.8–2.1 mm, brown, basifixed, concolorous, clathrate, margin entire or sparely denticulate, apex acuminate. Fronds strongly dimorphic, fertile fronds shorter or nearly the same length as sterile frond. Sterile fronds 45–49 cm tall, petiole shorter than lamina; laminae ribbon-lanceolate, margins entire, slightly repand, base cuneate, decurrent, apex acuminate, 37–39 cm long, 3.1–3.4 cm wide at middle, thinly chartaceous, glabrous; petioles stramineous, grooved adaxially, glabrous, 1.1–1.3 mm in diam., 11–13 cm long; venation anastomosing, lateral veins distinct, veinlets visible. Fertile fronds 42–47 cm tall, petioles the same length or longer than laminae; laminae linear, margins entire, base cuneate, apex long acuminate, 22–27 cm long, 0.8–1.0 mm wide at middle; petioles 1.1–1.2 mm in diam., 19–21 cm long. Sori acrostichoid, continuous along midrib.

Distribution and habitat: Leptochilus kachinensis is currently only known from the type locality in Kachin State, located in northern Myanmar. The species was observed growing on tree trunk.

Etymology: The species epithet is derived from Kachin State, where the species is found.

Note: The phylogenetic analysis resolved Leptochilus kachinensis as the sister species to the Colysis subclade in the Colysis clade ( Fig. 1 ). The close relationship between the new species and L. hemionitideus (C. Presl 1836: 216) Nooteboom (1997: 285) is confirmed by both of them having herbaceous sterile laminae and distinct venation.

Figures

FIGURE 1. Phylogeny of Leptochilus based on six plastid markers (modified from Zhang et al. 2024). Orange color indicates the new species described here.

FIGURE 5. Leptochilus kachinensis Liang Zhang & Li Bing Zhang,—A. Habit.—B. Venation.—C. Rhizome.