Hypodematium shingii Li Bing Zhang, X.P.Fan & X.F.Gao, 2021

Fan, Xue-Ping, Zhang, Liang, Knapp, Ralf, He, Hai, Gao, Xin-Fen & Zhang, Li-Bing, 2021, Hypodematium shingii sp. nov. (Hypodematiaceae; Polypodiales): Replacing the misapplied “ H. crenatum ”, a widespread fern from Asia, Phytotaxa 482 (1), pp. 87-92 : 88-91

Hypodematium shingii Li Bing Zhang, X.P.Fan & X.F.Gao , sp. nov. Figs. 1 & 2 .

Type:— CHINA. Yunnan: Lijiang City , Yongsheng County, Provincial Highway #308, 26°42’44’’ N, 100°43’3’’E, elev. 1760 m, 25 September 2018, Xue-Ping Fan FXP56 (holotype CDBI!) .

Diagnosis:— Hypodematium shingii is most similar to H. crenatum . Both species have dense acicular hairs on fronds and indusia, white hairs on petioles upward, and oblong lobes. However, H. shingii has fronds covered with long acicular hairs, dense gray hairs on rachis and costa, lobe apices with 3–4 prominent rounded serratures, and sori on medial veins. In contrast, H. crenatum has fronds covered with short acicular hairs, sparse gray hairs on rachis and costa, lobe apices with 6–8 shallow serratures, and sori on inframedial veins. In addition, the two taxa are distributed in different geographical areas with H. shingii being in southern China and northern Thailand and H. crenatum only in Arabia ( Table 1).

Description:— Plants 15–80 cm tall, yellowish green when dry. Rhizomes prostrate, swollen stipe bases covered with dense scales; scales reddish brown, lanceolate, 1.5 cm × 2 mm, membranaceous, apex acuminate, margins dentate. Leaves approximate; stipe reddish or stramineous, lustrous, 8–45 cm × 1–3.5 mm, distally with dense, acicular white hairs, nearly equal in length or shorter than lamina; lamina trigonal-ovate, base truncate or cordate, 10–45 cm × 5–26 cm, base quadripinnate or tripinnate, tripinnate or bipinnate distally, apex acuminate and pinnatifid; pinnae in 10–14 pairs, alternate, slightly oblique, basal pair largest, deltoid-ovate, base cordate, 5–30 cm × 3–15 cm, 0.4–2 cm stalked, 3-pinnate, apex acuminate; pinnules in 8–10 pairs, anadromous, alternate, oblique, acroscopic ones smaller, proximal basiscopic pair largest, triangular-lanceolate, shortly stalked, base cuneate, 2-pinnate, apex acuminate; ultimate pinnules in 5–8 pairs, oblong, base cuneate, connected to each other by narrow wings, 4–6-lobed; lobes oblong, each lobe with 3–4 large rounded serratures at apex, apex obtuse or truncate. Laminae chartaceous, fronds densely covered with acicular grayish white hairs on both surfaces, these 0.3–0.5 mm long, ca. 30 hairs/mm², margin covered with numerous acicular hairs; rachises and pinna rachises densely covered with grayish white hairs, especially on adaxial side, mixed with some linear lanceolate scales. Veins obvious on both surfaces, pinnate, free, reaching to margin, 4–6 each lobe. Sori orbicular, dorsal, 0.9–1.3 mm diam., 1–2 per lobe, located on middle of veinlets, usually separate when mature. Indusia persistent, grayish, reniform to rounded, densely covered with long grey hairs, these hairs 0.3–0.4 mm long, usually smaller than sori when mature.

Distribution: — Hypodematium shingii is distributed in subtropical China and northern Thailand. In China, this species is distributed in Chongqing, Guizhou, Hainan, Sichuan, Taiwan, and Yunnan. It might occur in neighboring eastern Myanmar, northern Laos, and northern Vietnam. It grows in limestone crevices.

Etymology: —The species epithet is in honor of Kung-Hsia Shing, based at PE, a specialist of Hypodematium and one of the authors of the original/Chinese Flora of China treatment of the genus ( Shing et al. 1999).

Taxonomic notes:— Hypodematium shingii has been treated as H. crenatum for a long time (e.g., Tsai & Shieh 1994, Shing et al. 1999, Zhang & Iwatsuki 2013, Wang et al. 2014). Our morphological observations ( Fig. 2 : D–F), combined with molecular analysis (Fan et al. unpubl. data), show that true H. crenatum (type from Yemen) occurs only in Arabia. Hypodematium shingii is distributed in China and Thailand.

Our research shows that Hypodematium taiwanense and the true H. crenatum are probably closely related, but H. shingii is a different species. H. crenatum and H. shingii are resolved in different branches in our molecular tree (Fan et al., unpubl. data). Hypodematium taiwanense and H. shingii are very different morphologically too. Hypodematium taiwanense has mixed glandular hairs and acicular hairs, stipes stramineous and glabrous, sporangia small, 0.5–0.8 mm, and indusia sparsely covered with hairs; while H. shingii has dense acicular hairs only, stipes usually reddish and densely covered with acicular hairs distally, sporangia large, 0.9–1.3 mm, and indusia densely covered with acicular hairs.

Selected additional specimens examined (paratypes): CHINA. Chongqing: Beibei District, Pianyan Township, Golden Knife Gap , 30°02’03.48’’N, 106°37’29.53’’E, elev. 500 m, 09 April 2011, Hai He & Yong-Qing Yang H 1099 (CTC!) . Guizhou: Duyun City, Gantang Township , 26°16’17.84’’N, 107°25’48.52’’E, elev. 944 m, 15 October 2012, Li-Bing Zhang & Hai He 6090 (CDBI!, CTC!) . Guizhou: Zhijin County, Jichang Township , 26°30’30’’N, 105°25’48’E, 13 August 2017, Li-Bing Zhang, Yi-Fan Duan & M. Kropf 9572 (CDBI!) . Sichuan: Dujiangyan City, Mt. Qingcheng, Tianran Pavilion , on creek cliff, elev. 800 m, 05 August 1984, Kung-Hsia Shing & Qun Xia 5021 (PE!) . Sichuan: Panzhihua City, Minzheng Township, Baguan River , limestone crevices on slopes, elev. 1300 m, 17 June 1983, Qinghai-Tibet Exp. 11209 (PE!) . Sichuan: Pengzhou City, Gexian Shan Township , limestone crevices, 05 March 2011, Liang Zhang 1410 (CDBI!). Taiwan : Nantou County, 23°33’N, 120°56’E, elev. 1520 m, 10 Jun 2016, R. Knapp 4166 (P!) . Yunnan: Kunming City, Panlong District, Mt. Changchong , limestone crevices, 25°7’26.72’’N, 102°42’8.21’’E, elev. 2260 m, 18 June 2017, Liang Zhang 1819 (KUN!) . Yunnan: Lijiang City, Yongsheng County, Provincial Highway #308, 26°42’44’’ N, 100°43’3’’E, elev. 1760 m, 25 September 2018, Xue-Ping Fan FXP55 (CDBI!) . THAILAND. Chiang Mai: Doi Chiang Dao , 19°25’N, 98°55’E, elev. 1050 m, limestone crevices in limestone ridge, 30 December 1968, E. Hennipman E3196 (L!) . Chiang Mai: Doi Chiang Dao , 19°19’0” N, 98°41’26” E, 1580 m, 08 Jul. 2019, Li- Bing Zhang, R. Pollawtn, Liang Zhang, P. Limpanasittichai 10572 (BCU!, CDBI!, KUN!, MO!, PYU!, XTBG!) . Loei: Tham Pha Sawan, Pha Khao District , T. Boonkerd et al. 2011-738 (BCU!) .

Figures

FIGURE 1. Hypodematium shingii Li Bing Zhang, X.P.Fan & X.F.Gao.—A. Habit.—B, D, F, G, K Pinnae or portion of pinnae.—C. Petiole.—E, H, J. Portions of laminae (A, B. Liang Zhang 1410 (CDBI); C–E. Liang Zhang 1819 (KUN); F–K. R. Knapp 4166 (P)).

FIGURE 2. A–C. Hypodematium shingii Li Bing Zhang, X.P.Fan & X.F.Gao.—A. Habit.—B. Abaxial view of portion of lamina.—C. Portion of pinnule/lobe showing sori (based on the type). D–F. H. crenatum (Forssk.) Kuhn & Decken.—D. Pinnule.—E. Adaxial view of portion of lobe.—F. Portion of pinnule/lobe showing sori (based on R. Spellenberg & M. Nasher 7345 (MO)).