Solenostoma (subg. Plectocolea) vidyasagariensis Sk. R.Islam, A.K.Mondal & D.Singh, 2025

Islam, Sk. Rasidul, Mondal, Amal Kumar & Singh, Devendra, 2025, Solenostoma (subg. Plectocolea) vidyasagariensis (Solenostomataceae: Marchantiophyta) - A new species from West Bengal, India, Phytotaxa 716 (3), pp. 216-222 : 216-220

Solenostoma (subg. Plectocolea) vidyasagariensis Sk. R.Islam, A.K.Mondal & D.Singh , sp. nov. ( Figs. 1–3 )

Holotype: India, West Bengal, Purulia district, Ajodhya hills , Vidyajara village , ca 532 m, 23 º 12 ʹ 48.18 ʺ N and 86 º 06 ʹ 28.81 ʺ E, 13 September 2019, Sk. R. Islam & A.K. Mondal 00968/09 ( holotype: CAL; isotype: Vidyasagar University Herbarium) .

Plants yellowish green when fresh, light brown-greenish brown as a dried herbarium specimen; prostrate, occasionally suberect, shoots 4–6 mm long, 1.5–2.0 mm wide including leaves, branching not seen. Stem transversely ellipsoidal in outline in cross section 260–320 × 230–280 µm, 7–9 cells across diameter; cells differentiated only in size, outer cortical cells 10.2–20.9 × 14–29.4 µm, inner medullary cells 11–37 × 15–48 µm, hyaline, thin-walled. Rhizoids scattered on ventral surface of stem and restricted only at the basal portion of leaf surface, brownish. Leaves imbricate, obliquely inserted, ovate, 0.5–1.0 mm long, 0.4–0.7 mm wide, apex rounded to obtuse or sometimes truncate, margin plane, base shortly decurrent dorsally, not decurrent ventrally; apical leaf cells subquadrate to polygonal, 31.3–43.0 × 21.0–28.0 µm; median leaf cells polygonal, 47.0–56.0 × 17.25–26.8 µm; basal leaf cells rectangular to polygonal, 62.8–66.3 × 20.0–22.5 µm, cells thin-walled, with indistinct trigones; cuticle smooth. Oil bodies not seen.

Dioicous (?). Male plants not seen. Gynoecial terminal on main shoot; female bracts in one pair, usually similar to leaves in shape, but larger in size, ovate, 2.1–2.4 mm long, 1.7–2.0 mm wide, margins entire; bracteoles absent. Perianth terminal on main axis, exerted for 1/3 of its length, fusiform, 2.0– 2.8 mm long, 1.2–1.6 mm wide, 5-plicate, mouth not beaked, crenulate, when young sporangium inside, upper part of perianth gradually narrowed, composed of elongate thin-walled cells; cells of upper part of perianth elongate to oblong, 93.04–117.5 × 22–27.3 µm, thin-walled, concave, trigones indistinct; cells of middle part rectangular, thin-walled, concave, 119.13–147 × 35.0–39.0 µm; cells of lower part similar to middle, 169.7–175.7 × 35.0–36.0 µm; 3–4 archegonia per perichaetium; perigynium absent. Seta circular-ovoid in outline in transverse section, 0.4–0.8 mm in diameter; capsule deep black when mature, circular–ovoid, 0.35–0.45 mm, 4-valved, each valve 0.7–0.9 mm long, 0.2–0.3 mm wide; wall bistratose, cells of outer layer of capsule subquadrate, 33.5–48.2 × 20.0–42.5 µm, with nodular thickenings in surface view, those of inner layer 45–110 × 28–50 µm, with usually complete or sometimes incomplete semi-annular bands in surface view. Spores light brown, globose 8–12 µm in diameter, surface lamellate forming false lamellate-reticuloid pattern, sometimes irregular folding appears like septa due to thin exine, each lamellae covered with granules. Elaters reddish brown, 70–135 µm long, 6–11 µm wide, with bispiral thickening bands and tapering ends.

SEM studies revealed lamellate sporoderm with reticuloid pattern or sometimes bifurcated and irregularly arranged lamellae covered with a warty like appearance or small tubercles throughout the surface of lamellae.

Habitat: Terricolous, growing in moist and shady places in tropical forest dominated by Shorea robusta Gaerthner (1805: 48) in association with Plagiochasma pterospermum Massalongo (1897: 46) , Fossombronia japonica Schiffner (1899: 389) and mosses.

Distribution: India, West Bengal (Purulia district, Ajodhya Hills), probably endemic. ( Fig. 4 )

Specimens examined: INDIA. West Bengal, Purulia district, Ajodhya hills , Vidyajara village , ca. 532 m, 29 October 2020, Sk. R. Islam & A. K. Mondal 00979/22 ( Paratype: Vidyasagar University Herbarium) .

Etymology

The species has been named after the renowned Indian educator and social reformer of the nineteenth century Pandit Ishwar Chandra Bandyopadhyay, also known as Ishwar Chandra Vidyasagar, who is considered the “Father of Bengali Prose”.

Figures

FIGURE 1. (A–W) Solenostoma (subg. Plectocolea) vidyasagariensis Sk. R. Islam, A.K. Mondal & D. Singh. A. Portions of the plant in dorsal view with sporophyte B. Transverse section of stem C–E. Leaves F. Apical leaf cells G. Median leaf cells H. Basal leaf cells I. A female bract J. Longitudinal section of perianth K. Cells in upper part of perianth L. Cells in middle part of perianth M. Cells in basal part of perianth N, O. Transverse sections of perianth P. Transverse section of seta Q, Transverse section of capsule wall R, Outer layer of capsule wall S, Inner layer of capsule wall T, U. Spores V, W. Elaters (All figures drawn by Sk. Rasidul Islam from the holotype, Sk. R. Islam & A. K. Mondal 00968/09)

FIGURE 2. (A–Q) Solenostoma (subg. Plectocolea) vidyasagariensis Sk. R.Islam, A.K.Mondal & D.Singh. A. Habit B. A portion of the plant in lateral view C. The same in ventral view D. The same in dorsal view E. Mature capsule along with seta F. Dehisced capsule G. Transverse section of stem H. A leaf I. Apical leaf cells J. Median leaf cells K. Basal leaf cells L. A female bract M. Transverse section of perianth N. Transverse section of seta O. Outer layer of capsule wall P. Inner layer of capsule wall Q. Spores (All photomicrographs taken by Sk. Rasidul Islam from the holotype, Sk. R. Islam & A. K. Mondal 00968/09)

FIGURE 3. (A–F) Solenostoma (subg. Plectocolea) vidyasagariensis Sk. R. Islam, A. K. Mondal & D. Singh SEM images. A. Spores and elaters B–C. Spores D, E. Portions of the same enlarged F. An elater (All photomicrographs taken by Sk. Rasidul Islam from the holotype, from Sk. R. Islam & A. K. Mondal 00968/09)

FIGURE 4. Distribution map of Solenostoma (subg. Plectocolea) vidyasagariensis Sk. R. Islam, A. K. Mondal & D. Singh