Plagiochila meagheriana S.Majumdar & M.Dey, 2025

Plagiochila meagheriana S.Majumdar & M.Dey sp. nov.

Diagnosis: Similar to P. peculiaris , however, differs in having exposed stem surface, both dorsally and ventrally; horizontally spreading rectangulate leaves with truncate apices that are much longer than wide (length:breadth ratio 1.8–2.8:1) and dimorphic cells in leaves of different portions of the shoot, i.e., leaf cells are vermiculate in leaves of the younger portion of the shoot while leaf cells are non-vermiculate, with medium to large nodulose trigones in the leaves of the older portion of the shoot.

Type: India, Eastern Himalaya, West Bengal, Darjeeling district, Lepchajagat, 27°00’47”N, 88°11’55”E, 2283 m, 05 September 2016, M. Dey 81077A ( Holotype CAL!).

Plants dark brown, 4–8 cm long, 4.0– 6.2 mm wide including leaves, irregularly branched; branching rare, when present lateral intercalary, only on the older portion of shoot. Stem exposed both dorsally and ventrally, broadly elliptical in outline in transverse section, 202–303 × 303–455 μm, 14–19 cells across diameter, cortical cells in (2–) 3–4 cell layers, more or less rectangulate–subquadrate or polygonal, (2.5–) 5.0–15.0 × 7.5–30.0 μm, thick-walled, reddish brown, trigones small to indistinct; medullary cells rectangulate–subquadrate or polygonal, 7.5–25.0 × 10–35 μm thin-walled, yellowish–hyaline. Paraphyllia absent. Creeping rhizome not seen. Rhizoids few, arising from the older portion of the aerial shoots, also present (very few) on the branches. Leaves distant–contiguous in apical one-third portion of the shoot, while contiguous–imbricate in middle to lower portion of the shoot, horizontally spreading, moderately fragmenting, rectangulate with truncate apex, 2.0– 2.7 mm long, 0.9–1.4 mm wide, length:breadth ratio of leaves 1.8– 2.8:1; leaves highly revolute in the apical and median portion of the shoot, dorsal margin almost straight, mostly entire, rarely with 1–2 small teeth towards apex, base long decurrent, apex truncate, irregularly dentate, ventral margin with small undulation, sometimes with 1–2 small teeth towards apex, slightly ampliate towards base, base short decurrent; teeth 4–8 (–10) per leaf, 1–7 cells long, 2–4 cells wide at base, 1–4 cells uniseriate towards apex, terminal leaf cells acute–acuminate, 14–32 (–40) × 8–16 μm, length:breadth ratio 1.8–4.5:1; apical and subapical leaf cells 14–30 × 8–24 μm, cells vermiculate in leaves of the younger portion of the shoot, non-vermiculate, with medium to large nodulose trigones in the leaves of the older portion of the shoot; median leaf cells 20–40 × 14–26 μm, leaf cells vermiculate in leaves of younger portion of shoot, non-vermiculate, with medium to large nodulose trigones in leaves of older portion of shoot; basal leaf cells slightly elongated, (20–) 25–58 × 15–30 μm, cells vermiculate in leaves of younger portion of shoot, non-vermiculate, with nodulose–confluent trigones, interrupted by intermediate thickenings in leaves of older portion of shoot, vitta-like area absent; surface smooth. Underleaves vestigial. Asexual reproduction by regenerates originating from the ventral surface of leaves. Fertile plants not seen.

Etymology

The species has been named to honour the renowned Australian bryologist, Dr. David Meagher.

Habitat and Ecology

Epiphytic, growing in very moist and shady environments, in association with Bazzania ovistipula ( Stephani 1908: 760) Abeywickrama (1959: 45)

Distribution

India [Eastern Himalaya ( West Bengal)], endemic.