Dicranum nepalense W.Z.Huang, T.X.Zheng & Y.Huan Wu, 2024

Dicranum nepalense W.Z.Huang, T.X.Zheng & Y.Huan Wu , sp. nov. ( Figs. 1–3 View FIGURE 1 View FIGURE 2 View FIGURE 3 )

≡ Dicranodontium nepalense Tak., J. Hattori Bot. Lab. 46: 375. 1979. nom. nud.

Differing from all other taxa of the genus Dicranum View in CoL in the combination of the following characters: invariably fragile View in CoL leaves, entire leaf apex, laminal cell in upper leaf mainly rectangle, elongate and porose, absence of stereid bands in the costal cross-section, only with one layer of guide cells and one layer of cells below the guide cells, abaxial surface of the costa is smooth throughtout, and bistratose alar cells.

Type: — NEPAL. The Annapurna Range, Upperkharka below Lamjung Himal., ca. 3600 m alt., on Rhododendron , 1 May 1976, S. Kunisawa et al. s.n. [holotype: NICH 349870!, isotype: BJTC!, HTC!].

Description. Plants in loose tufts, slightly glossy. Stems 0.7–1.5 cm, reddish brown to black, simple or rarely branched. Cross-section of stem rounded to oval, diameter (0.16–) 0.2–0.3 mm, consisting of 2–3 layers of smaller, rather thick-walled outer cortical cells, 3–5 rows of inner cortical cells, and 3–5 differentiated central strand cells. Leaves erectflexuose to falcate-secund, lanceolate at base, gradually tapering into a canaliculated apex, 4.5–8.5 × 0.35–0.62 mm. Leaf apex brittle, lacking in many lower leaves, except at stem apex; some leaves fractured at the leaf base, leaving only residual alar cells on the stem, form a leafless section on the stem. Leaf margins entire. Costa ca. 1/12–1/10 of leaf width at base, 40–55 μm wide at leaf base, filling most of the subula, abaxial surface smooth throughtout. Transverse section of the costa with one row of large empty cells (guide cells) in the upper side, and one row of slightly smaller cells below, without stereid bands. Leaf lamina unistratose. Upper and middle laminal cells rectangular, thick-walled, strongly porose, 45–75(–100) × 6–10 μm; basal laminal cells rectangular to elongate-rectangular, thick-walled, strongly porose, (50–)70–100(–120) × (12–)14–22 μm; basal marginal cells narrower, linear, walls not pitted, 40–50 × 4–7 μm; alar patches distinct, brownish black, extending to the costa, alar cells square to short-rectangle, bistratose, (29–)25–35(–50) × (18–)20–22 μm. Sporophytes not seen.

Etymology. The epithet ‘‘nepalense’’ is named after Nepal, where this new species was found.

Ecology and distribution. Dicranum nepalense is known only from Nepal. This species has been exclusively observed growing on Rhododendron at elevations ranging from 2800 m to 3600 m.

Additional specimens examined (paratypes). NEPAL. The Annapurna Range , around the base camp below Lamjung Himal, 3600 m alt., on tree (mainly Betula ), 7 Apr. 1976, S. Kunisawa et al. s.n. ( NICH 349523 About NICH , BJTC, HTC) ; The Annapurna Range , Bakrekharka below Lamjung Himal, ca. 2800 m alt., on Rhododendron , 1 May 1976, S. Kunisawa et al. s.n. ( NICH 349893 About NICH , BJTC, HTC), S. Kunisawa et al. s.n. ( NICH 349896 About NICH , BJTC, HTC), S. Kunisawa et al. s.n. ( NICH 349898 About NICH , BJTC, HTC), S. Kunisawa et al. s.n. ( NICH 350911 About NICH , BJTC, HTC) ; Do., 3 May 1976, S. Kunisawa et al. s.n. ( NICH 350819 About NICH , BJTC, HTC) .