Leptochilus brevipes Liang Zhang, Zhen Long Liang, & Zhi Yong Yu, 2024

Yu, Zhi-Yong, Liang, Zhen-Long, Hu, Yu-Ping, Liang, Zong-Li, He, Hai-Long, Li, Jian-Hong & Zhang, Liang, 2024, Leptochilus brevipes (Polypodiaceae), a new fern species from southeastern Yunnan, China based on morphological and molecular evidence, Phytotaxa 634 (2), pp. 143-152 : 144-147

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

( Figs. 1 , 2 ).

Type:— CHINA. Yunnan: Jinping County, Jinhe Town , Banbanqiaocun , elev. 1527 m, 22°48’12.4”N / 103°11’38.2”E, on limestone rocks or tree trunks in disturbed evergreen broad-leaved forests, 26 May 2023, Zhi-Yong Yu, Jing Zhao, Yong-Ling Qiu, Jian-Jun Yang & Zhi-Qiang Ma BBC-13 (holotype KUN!; isotypes CDBI!, KUN!, PYU!) .

Diagnosis: Leptochilus brevipes is most similar to L. decurrens in having strongly dimorphic fronds, slightly distinct venation, and decurrent lamina base. However, L. brevipes is distinguished by its sterile frond with lanceolate lamina and petiole less than 4 cm long, contrasting the sterile frond of L. decurrens with narrowly ovate to ovate lamina and petiole often more than 5 cm long.

Plants perennial, evergreen. Rhizomes long creeping, 1.9–2.5 mm in diam., dorsiventrally flattened, scaly, with a few short phyllopodia and roots; cross section of rhizome with 5–6 vascular bundles, sclerenchyma strands 38– 49. Scales narrowly ovate or lanceolate, 1.8–2.3 × 0.4–0.7 mm, brown, basifixed, slightly spreading, concolorous, clathrate, margin entire or sparsely denticulate, apex acuminate. Fronds strongly dimorphic, fertile frond slightly longer than or nearly the same length as sterile frond, sometimes shorter than sterile frond. Sterile fronds 24–35 cm tall, petiole much shorter than lamina; lamina simple, lanceolate, margins entire, slightly repand, base broadly decurrent to petiole base, apex acuminate, 22–34 cm long, (1.8)2.1–2.6(4.2) cm wide at middle, thickly herbaceous, glabrous; costae stramineous, glabrous or slightly scaly abaxially, raised on adaxial surface, distinctly raised on abaxial surface; petiole stramineous, glabrous or slightly scaly, wingless petiole short, 0.8–1.4 mm in diam., (0.4) 1.1–3.9 cm long; veins anastomosing; primary veins ca. 60° to 100° from costa, forked, dark and distinct, gradually becoming indistinct towards lamina margins; veinlets between primary veins visible, connecting into multiple areoles, varying in size and shape, included veinlets often present in areoles; a row of areoles along costa, typically one to three costal areoles between two primary veins. Fertile fronds 16–38 cm tall, petiole almost the same length as lamina, sometimes slightly longer or shorter than lamina; lamina linear, gradually narrowed towards base, apex acuminate, 16–27 cm long, 1.8–2.3 mm wide at middle; petiole stramineous, 0.7–1.3 mm in diam., 7–23 cm long. Sori acrostichoid, covering whole surface of abaxial lamina.

Additional specimens examined (paratypes):— CHINA. Yunnan: Xichou County, Fadouxiang, Shuichong , elev. 1550 m, wet rocks by streams in evergreen broad-leaved forests, 15 January 1978, Zhong-Ren Wang 574 ( PE!) ; Fadouxiang, Dongzongcao , elev. 1400 m, limestone in evergreen broad-leaved forests, 17 January1978, Zhong-Ren Wang 611 ( PE!) ; Jinping County, Jinhe Town, Banbanqiaocun , elev. 1550 m, 22°48’10.9”N / 103°11’29.7”E, on tree trunk in disturbed evergreen broad-leaved forests, 10 September 2019, Zhen-Long Liang, Wen-Hong Chen & Zhi-Yong Yu 613 ( KUN!) ; ibid., 11 September 2023, Zhi-Yong Yu & Zong-Li Liang YZY-JL-001 ( KUN, CDBI!) ; Jinping County, Jinshuihe Town, Xilongshan , elev. 1980 m, 22°35’21.2”N / 102°53’02.6”E, on limestone rocks with thick soil in disturbed evergreen broad-leaved forests, 30 May 2023, Jing Zhao, Zong-Li Liang, Yong-Ling Qiu & Jian-Hong Li XLS-238 ( KUN!) ; Malipo county, Laojunshan , 1600 to 1900 m, in mixed forests, 10 December 1947, K.-M. Feng 13768 ( PE!) .

Geographical distribution:—Currently, Leptochilus brevipes was found in Xichou County, Jinping County, and Malipo County of southeastern Yunnan, China. The species may also occur in limestone regions in northern Vietnam.

Ecology: — Leptochilus brevipes was observed growing on limestone rocks or tree trunks within slightly disturbed forests, at elevations between 1400 and 1980 m. In the locality where the type specimen was collected, up to 1000 individuals were discovered, with approximately two-thirds growing on rocks and one-third on tree trunks. Fertile fronds were observed in both epipetric and epiphytic habitats. The individuals growing on tree trunks with their roots extending into the soil, matching the criteria for categorization as a hemiepiphytic species according to Zotz (2013) and Zotz et al. (2021). However, the predominant growth habit of L. brevipes is epipetric, making it inappropriate to categorize the species as a hemiepiphyte.

Etymology: — The species epithet brevipes refers to a short petiole of the sterile frond, or sometimes indistinct petiole due to the sterile lamina decurrent to petiole base.

Vernacular name:—ÑĒAE唇″ (duan bing bao chun jue)

Figures

FIGURE 1. Leptochilus brevipes.—A. Habit of the new fern on rock.—B. Habit of the new fern on tree trunk.—C. Rhizome.—D. Portion of fertile frond.—E. Lower portion of abaxial lamina of sterile frond.—F. Upper portion of abaxial lamina of sterile frond.—G. Middle portion of abaxial lamina of sterile frond. Photo credit: Zhen-Long Liang & Jing Zhao.

FIGURE 2. Leptochilus brevipes.—A. Habit.—B. Portion of lamina.—C. Cross section of costa.—D. Cross section of rhizome. Stippled: vascular tissue; black: sclerenchyma strands.—E. Rhizome scale (drawn by Zhen-Long Liang based on the isotype at CDBI).