Hedwigia sinica W.Z.Huang & R.L.Zhu, 2024

Huang, Wen-Zhuan, Ma, Wen-Zhang, Ignatov, Michael S., Ignatova, Elena A., Sulayman, Mamtimin, Wu, Yu-Huan & Zhu, Rui-Liang, 2024, A taxonomic revision of Hedwigia (Hedwigiaceae, Hedwigiales) in China, Phytotaxa 634 (3), pp. 215-234 : 226-229

Hedwigia sinica W.Z.Huang & R.L.Zhu , sp. nov. ( Figs. 5−8 )

Diagnosis: —Similar to Hedwigia czernyadjevae , but differing in the slenderer leaves with length/width ratio of (2.5−)2.9−3.3(−3.9), sparse hairs at the base of calyptrae, and obovate to obconic capsules that are broadest just below mouths.

Etymology:— The epithet ‘‘sinica’’ is named after China, where this new species was found.

TYPE:— CHINA. Yunnan: Lijiang City, Baisha County, Alpine Botanical Graden towards Yu-Long Reservoir , 27°0′8″ N, 100°11′13″ E, 3150 m, on rock, 9 Aug. 2021, W. Z. Ma 21-12332 (holotype: KUN!; isotype: HSNU!) .

Description:— Plants in loose tufts, dark brown below, yellowish-green above. Stems branched, up to 5 cm long. Cross-section of stem rounded, consisting of 2–4 layers of smaller, thick-walled outer cortical cells, numerous rows of larger and thinner-walled inner cortical cells, central strand cells not differentiated. Stem leaves spirally arranged, wide-spreading to recurved when moist, erect-spreading when dry, with straight apices, rarely secund. Leaves longovate or lanceolate, (1.8−)2.3−3.0(−3.4)× 0.7−1.1 mm, with length/width ratio of (2.5−)2.9−3.3(−3.9), recurved at lower 3/4 or to the base of hair-point. Hyaline leaf apices 0.4–1.2 mm long, constituting (15−)30−45% of leaf length, margins of hair-points entire or with few sharp teeth at the distal portion. Abaxial surface of hyaline leaf apices covered with simple and branched papillae; median leaf cells thick-walled, porose, 11−20×5−10 μm, on abaxial surface mainly with single, large, branched, peltate papilla per cell, rarely with two papillae, and on adaxial side with one similar but smaller papilla. Cells in the leaf base linear, porose, 33−67×7−11 μm, with 2−5 simple papillae per cell, alar cells more or less quadrate, 9−18×7−13 μm.

Autoicous; male bracts small, apices obtuse or acuminate, 0.63−0.83× 0.33−0.46 mm; perichaetial leaves oblong, gradually narrowed to the apex, broadest slightly above the middle, 4.3−4.7× 1.1−1.3 mm, cilia long, uniseriate distally and 1−3 cells wide in the basal portion. Capsules immersed, obovate to obconic, broadest just below mouths, 1.7−2.0× 1.3−1.6 mm, with immersed stomata at base of the urn; peristome and annulus absent; exothecial cells in the middle of urn rectangular or short rectangular, at urn mouth in several rows smaller and darker colored. Setae 0.05−0.2 mm; calyptrae conical, with sparse hairs at the base. Spores 20−26 μm in diameter, triangular-globular, light brown, with worm-like papillae on the distal surface, proximal face appearing smooth.

Note:— Hedwigia sinica could potentially be misidentified as H. detonsa (M. Howe 1897: 91) W.R.Buck & D.H.Norris (1996: 368) , H. stellata , and H. czernyadjevae owing to the presence of one single, branched papilla per cell on abaxial side of median laminal cells in all these species ( Eckel 2014; Ignatova et al. 2016). However, the perichaetial leaf margins in H. detonsa are entire, lacking cilia at margins, which distinguish this species well ( Buck & Norris 1996; Eckel 2014), whereas perichaetial leaves in H. sinica are ciliate ( Fig. 6D ). Hedwigia stellata , which is fairly easy to recognize in nature, is distinguished by its reflexed or recurved leaf tips, giving the shoot tip a starry appearance when dry ( Hedenäs 1994; Buck & Norris 1996; Atherton et al. 2010; Eckel 2014; Ignatova et al. 2016). In contrast, H. sinica has straight and erect-spreading leaf tips ( Figs. 5D , 8A ). One of the main microscopic characteristics that distinguishes H. sinica from H. stellata is the presence of porose median laminal cells in the former ( Fig. 6F ), while they are smooth, not porose in the latter ( Ignatova et al. 2016). In addition, H. sinica differs from H. czernyadjevae by having (1) more slender leaves with a length/width ratio of (2.5−)2.9−3.3(−3.9) ( Figs. 6A ), (2) sparse hairs at the base of calyptrae ( Fig. 7B ), and (3) obovate to obconic capsules that are broadest just below the mouths ( Fig. 7A ). On the other hand, H. czernyadjevae has a length/width ratio of (1.7−)2.1−2.6(−3.0) in its leaves ( Fig. 2A ; Ignatova et al. 2016), calyptrae with strong hairy coverage throughout ( Fig. 3D ), and ovate to obovate capsules with the broadest part shortly above the middle ( Fig. 3C ).

Distribution and habitat:— This species is found so far only in China, where it typically thrives on marble rock walls in sunny locations, and usually is associated with Bryoerythrophyllum alpigenum ( Juratzka 1882: 98) P.C. Chen (1940: 5) , Bucklandiella subsecunda (Hooker & Greville ex Harvey 1836: 1) Bednarek-Ochyra & Ochyra in Ochyra et al. (2003: 147), Dicranum flagellare Hedwig (1801: 130) , Herbertus Gray (1821: 678) , and Pseudohygrohypnum calcicola ( Ando 1958: 167) Jan Kučera & Ignatov in Kučera et al. (2019: 650), at altitudes ranging from 2830 m to 3511 m.

Additional specimens examined:— CHINA. Sichuan: Ganzizangzu Autonomous Prefecture , Xiangcheng County, along a cascading stream (name not determined), 28°47′49.0″ N, 99°55′00.0″ E, 3500 m, on granitic rock above stream in sun, 23 Sept. 2016, James R. Shevock 48994 ( KUN) ; Ganzizangzu Autonomous Prefecture, Daocheng County, Sheng-Mu Township , along Dao-Cheng River near Ri-Huo Village , 29°2′49.0″ N, 100°33′44.0″ E, 3450 m, on granitic rock, 28 Aug. 2018, W. Z. Ma 18-9821 ( KUN) . Yunnan: Dali City, Cangshanerhai National Nature Reserve, Xiaoceng Peak , 25°40′46.22″ N, 100°6′24.97″ E, 3213 m, on rock, 6 Sept. 2023, R. L. Zhu et al. 20230906-37 ( HSNU) ; Shangri-La City, Shangri-La County , Luoji County, Ni-Ru Village , along Ni-Ru River , 27°57′16″ N, 100°3′42″ E, 2830 m, on rock, 18 Sept. 2016, W. Z. Ma 16-7782 ( KUN) ; Shangri-La City, Shangri-La County , Luoji County, Ni-Ru Village , lower slopes of Pielongshan , along a 10 km trail to ‘ Colorful Rainbow Waterfall’ of the Ni-Ru River , between second stream crossing and the falls, 27°57′45.0″ N, 100°01′58.7″ E, 3270 m, on marble rock wall in sun to filtered light, 19 Sept. 2016, James R. Shevock 48936 ( KUN) ; Shangri-La City, Shangri-La County , Luoji County, along trail from Ni-Ru village to Gu-Zhong pasture, 3060 m, On rock, 10 Jul. 2023, W. Z. Ma 14476 ( KUN) ; Zhaotong City, Qiaojia County, Yaoshan Town , Yaoshan National Nature Reserve , on the way to the summit, from Dawo to Longtan , 27°12′40.7″ N, 103°5′23.45″ E, 3511 m, on granitic rock in sun, 11 Nov. 2021, W. Z. Huang & H. Xu 20211111-3 ( HSNU) .

Figures

FIGURE 2. Hedwigia czernyadjevae Ignatova, Ignatov & Fedosov. A. Leaves; B. Leaf apex; C. Male bracts; D. Perichaetial leaf; E. Papillae in mid-leaf on abaxial surface; F. Cell areolation in mid-leaf, showing thick-walled and porose cell walls; G. Papillae in mid-leaf on adaxial surface; H–I. Cells in the middle of leaf base; J. Basal marginal cells. K. Cross section of stem; L. Leaf transverse sections.All from R.L. Zhu et al. 20220803-304 (HSNU).

FIGURE 3. Hedwigia czernyadjevae Ignatova, Ignatov & Fedosov. A. Plants when dry; B. Plants when wet; C. Capsule; D. Calyptra; E. Exothecial cells in the middle of urn; F. Operculum; G. Stoma; H. Spores.All from R.L. Zhu et al. 20220803-304 (HSNU).

FIGURE 5. Hedwigia sinica W.Z.Huang & R.L.Zhu. A–C. Habitat of the holotype specimen (patches of H. sinica are arrowed); D. Plant when dry; E. Plant when wet, showing male and female inflorescences on the same stem (autoicous sexual condition). All from W.Z. Ma 21-12332 (holotype).

FIGURE 6. Hedwigia sinica W.Z.Huang & R.L.Zhu. A. Leaves; B. Leaf apex; C. Male bract; D. Perichaetial leaf; E. Papillae in mid-leaf on abaxial surface; F. Cell areolation in mid-leaf, showing thick-walled and porose cell walls; G. Papillae in mid-leaf on adaxial surface; H–I. Cells in the middle of leaf base; J. Basal marginal cells. K. Cross section of stem; L. Leaf transverse sections. All from W.Z. Ma 21-12332 (holotype).

FIGURE 7. Hedwigia sinica W.Z.Huang & R.L.Zhu. A. Capsule; B. Calyptra; C. Exothecial cells in the middle of urn; D. Operculum; E. Stoma; F. Spores. All from W.Z. Ma 21-12332 (holotype).

FIGURE 8. SEM images of Hedwigia sinica W.Z.Huang & R.L.Zhu. A. Plant. B. Subapical part of leaf, dorsal view; C–D. Papillae in mid-leaf on abaxial leaf surface. E–L. Spores. All from W.Z. Ma 21-12332 (holotype).