Hymenasplenium chingii K.W. Xu, Li Bing Zhang & W.B.Liao, 2018

Xu, Ke-Wang, Zhang, Liang, Lu, Ngan Thi, Zhou, Xin-Mao, He, Hai, Luong, Thien Tam, Knapp, Ralf, Liao, Wen-Bo & Zhang, Li-Bing, 2018, Nine new species of Hymenasplenium (Aspleniaceae) from Asia, Phytotaxa 358 (1), pp. 1-25 : 2-5

Hymenasplenium chingii K.W. Xu, Li Bing Zhang & W.B.Liao , sp. nov. ( Figures 1 , 2 ).

Type:— CHINA. Yunnan: Malipo, Xiajinchang Xiang, Yunling Cun, Liangzishang , 23°0’22”N, 104°49’39”E, elev. 1800 m, on wet rocks along a stream near road, 11 December 2015, Ke-Wang Xu, Long-Yuan Wang & Hui-Zhe Feng TTJ-YN-030 (holotype SYS! , isotypes MO! , SYS! ).

Diagnosis:— Hymenasplenium chingii is somewhat similar to H. hondoense ( Murakami & Hatanaka 1988: 191; Nakaike 1992: 841) in having pinnae falcate or trapeziform and teeth at base of the pinnae often slightly retuse, but the former has pinna apex acute or acuminate and sori supra-medial to (sub)marginal, while the latter has pinna apex subacute to obtuse and sori medial.

Plants perennial, evergreen, 20–38 cm tall. Rhizomes long creeping, ca. 2.5 mm in diam., apex scaly, scales dark brown, narrowly triangular or lanceolate, margins nearly entire, (0.1–)0.4 × 1–1.2 mm; root yellowish brown when dried, slender, up to 8 cm long, ca. 0.25 mm diam, densely covered with yellow brown woolly indument or subglabrous. Fronds remote, 10–12 mm apart, herbaceous; petioles shiny, dark brown, 6–15 cm long, ca. 1 mm in diam., base near rhizome sparsely covered with scales, scales narrowly triangular, dark brown, margins nearly entire, 0.2 × 0.5–0.8 mm, and densely covered with yellow brown woolly indument. Laminae narrowly ovate, 1-pinnate, 12–22 × 3.5–6 cm, widest near base, gradually narrowing toward apex, apex acute; rachises 0.5–1 mm in diam., glabrous, shiny, dark brown, adaxial side grooved and with 2 green narrow wings. Pinnae shortly stalked to almost sessile at apex, 15–30 pairs, alternate, falcate or trapeziform, (middle pairs) 1.5–3 × 0.4–0.7 cm, about 3–6 mm apart, base asymmetrical, acroscopic side truncate and subparallel or forming an angle less than 15° with rachis, basiscopic side cuneate, with ca. 10 mm absent (calculated from the base to the first tooth appearing in the margin of basiscopic side), acroscopic margins serrate, teeth acute or obtuse, usually retuse at basal portion of pinnae, basiscopic margins entire at base, serrate in the middle and apex; pinna apex acuminate. Veins visible on both sides of pinnae, stramineous, rarely brown near pinnae petioles, lateral veins visible abaxially but obscure adaxially, forking and terminating in marginal teeth or below notches, 2–4 basal basiscopic veins lacking. Sori linear, 2–3(–4) mm long, medial, (1–)5–7 on acroscopic side and (1–)4–6 on distal basiscopic side of the pinnae in the middle part of the laminae, centers 1–2(–5) mm apart from one another; indusia brown, linear, membranous, entire, the indusium of the first sorus on the acroscopic side of pinnae opening toward rachis or absent, other indusia opening toward costa.

Geographical distribution:— Hymenasplenium chingii is found in Guizhou and Yunnan, Southwest China.

Ecology:— Hymenasplenium chingii was observed to grow on wet rocks along streams with shady conditions under broad-leaved forest.

Etymology:—The species epithet is in honor of the late professor Ren-Chang Ching based at PE for his great contributions to Chinese pteridology in general and to the taxonomy of Hymenasplenium in particular ( Ching 1965, Ching & Liu 1983).

Vernacular name:— Àkůďäffǎ (qin shi mo ye tie jiao jue).

Taxonomic notes:—Morphologically, Hymenasplenium chingii is similar to H. hondoense (see above). Phylogenetically, H. chingii was resolved as sister to a clade containing H. hondoense , H. wangpeishanii , and H. speluncicola ( Xu et al. 2018a) . Our large sampling in the molecular analysis suggested that H. hondoense , with its type from Honshu, Japan, probably does not occur in China, contrasting the report of the latter in China by Lin & Viane (2013).

Additional material examined:— CHINA. Yunnan: Gongshan, Cikai, Qiqigou , elev. 1550 m, 13 August 2011, Xiaohua Jin & Liang Zhang 11347 (CDBI!) ; Guizhou: Nayong, Yangchang Zhen, Qinglin Cun , Black Cave , 26°41’3”N, 105°10’27”E, elev. 1570 m, 23 August 2017, Li Bing Zhang, Yi-Fan Duan & Matthias Kropf 9780 (CDBI!) ; Guizhou: Libo, Xiaoqikong Zhen, Chuandong , 25°43’20”N, 107°56’46”E, elev. 950 m, 3 August 2017, Li Bing Zhang, Yi-Fan Duan & Matthias Kropf 9455 (CDBI!) .

Figures

FIGURE 1. Hymenasplenium chingii K.W. Xu, Li Bing Zhang & W.B.Liao.—A. Habitat and plants.—B. Plants.—C. Adaxial lamina.— D. Abaxial lamina.—E. Pinnae shape and sorus distribution.

FIGURE 2. Hymenasplenium chingii K.W. Xu, Li Bing Zhang & W.B.Liao.—A. Habit.—B. Portion of abaxial lamina.—C. Portion of adaxial lamina.