Orthomnion javense (Fleischer) Koponen (1980: 53)

Omar, Ichha, Nair, M. C., Asthana, A. K. & Asthana, Geeta, 2020, Orthomnion javense (Mniaceae, Bryophyta), new to India and Nepal, Phytotaxa 432 (3), pp. 283-288 : 284

Orthomnion javense (Fleischer) Koponen (1980: 53) .

Mnium javense Fleischer (1904: 585) .

Lectotype (designated by Koponen1980):— West Java: Gedehbei, Tjibodas an waldbäumen , 1400 m, July 1898, M. Fleischer ( FH) (not seen) ( Figs 1. A–T , 2. 1 –24).

Plants slender, lax, 2.5–5cm long. Stems brownish, creeping, densely radiculose, 0.3–0.45mm in diameter, in cross section differentiated into outer 2–3 layered thick-walled cortical cells 7.5–15×7.5–11.25 µm and inner thin-walled medullary cells 22.5–37.5 × 30–37.5 µm. Leaves green, fragile, thin, crisped when dry, distantly arranged, elliptic to broadly ovate, 3–5 mm long and 1.6–2.5 mm wide; leaf base not decurrent; apex acute to obtuse, often having group of few quadrate cells on both the sides of a small apiculus (86–160 µm); margin entire; border differentiated, 2–3(–4) cells wide, frequently extended to near apex, occasionally merging into the apiculus or completely diffused at apex, border cells thin walled, linear rectangular to rhomboidal 93.75–123.75(–168.75) × 7.5 µm; costa strong, brown, covering more than half of the leaf length, often vanish near apex or rarely reaching the apex; leaf apical cells quadrate to subquadrate (18.75–)22.5–30(–33.75) × 18.75–22.5 µm, middle cells subquadrate to hexagonal (26–)30–45 × 18.75–37.5(–41.25) µm, thin walled, not pitted, corner thickenings absent, basal cells elongated rectangular 41.25–60 × (22.5–)26.25–30 µm. Sexuality dioecous, fertile plants with creeping stem of ± 3cm giving rise to upright erect branches of 1 cm in length containing archegonia; perichaetial leaves long spathulate 4.2 × 2 mm, crowded at apex, apex of leaves often brittle and decayed. Sporophyte not seen.

Distribution: — China, India (Karnataka), Indonesia, Japan, Laos, Nepal, Papua New Guinea, Philippines and Vietnam.

Specimens examined: — INDIA. Karnataka: Chikkaballapur district, Nandi hills, 1400 m, 5August 2018, Sabarish 15638 (ZGC) ; NEPAL. Between Bir Gaon and Dingla , 1610 m, 1 July 1972, Z. Iwatsuki no. 2130 (NICH—313167 (paratype of O. noguchii ).

Figures

FIGURE 1. A–T: Orthomnion javense: A–B) Fragile plants. C–F) Leaves. G) Cross section of stem. H) Cross section of leaf costa, I–L) Variations in apex of leaves. M–O) Bordered base of leaves. P–Q) Leaf showing 2–3 cells wide border. R) Cross section of leaf border. S) Middle laminal cells of leaf. T) Perichaetial leaves showing archegonia. (A,E–F,H–K,M–N,Q–R from ZBC 15638 & B–D,G,L,O,P,S–T from NICH 2130)

FIGURE 2. 1–24: Orthomnion javense: 1) Fragile plant. 2–6,8–10) Leaves. 7) Perichaetial leaf.11) Moderately bordered apex of leaf. 12) Unbordered apex of leaf. 13–15) Middle cells of leaf. 16–17) Basal cells of leaf. 18) Leaf border from base towards middle. 19–20) Leaf border in middle portion of leaf. 21) Leaf border from middle vanishes towards apex. 22–23) Cross section of leaf costa. 24) Cross section of leaf border.(1,3–5,9–11,13–14,17–19,22,24 from ZBC 15638 & 2,6–8,12,15–16,20–21,23 from NICH 2130).