Lejeunea tjibodensis (Steph.) G.E.Lee & Heinrichs, 2018

Lee, Gaik Ee, Bechteler, Julia & Heinrichs, Jochen, 2018, A revision of unrevised taxon names in the former genus Taxilejeunea (Marchantiophyta: Lejeuneaceae) from Asia, Phytotaxa 358 (1), pp. 26-48 : 40

8. Lejeunea tjibodensis (Steph.) G.E.Lee & Heinrichs , comb. nov., Fig. 8 .

Hygrolejeunea tjibodensis Stephani (1914: 571) . Taxilejeunea tjibodensis (Steph.) Eifrig (1937: 91) .

Type: INDONESIA. Java: Tjibodas, Nyman s.n. (lectotype G 16248 ! [c.per. and spor.], here designated; isolectotype JE!) .

Plants dioicous, 1.0–1.3 (1.6) mm wide, irregularly and slightly branched, rarely bipinnately branched, branches erect-spreading, with three large basal collar lobes. Stem 0.10–0.15 mm in diameter, about 6 cells high in cross-section; epidermal cells 9, 20–50 μm wide, medullary cells 14–18, 13–33 μm wide. Leaves imbricate, recurved and often crisped when dry, erect-spreading and recurved when moist. Leaf lobes 0.50–0.85 mm × 0.40–0.65 mm (when flattened), ovate-oblong; leaf apex acute to apiculate, recurved; leaf margin entire to slightly crenulate; the ventral margin forming an angle of 110°–130° with the keel when flattened; insertion 16–18 lobe cells long. Leaf cells rather uniform, pentagonal to hexagonal; apical cells 20–25 μm × 20–25 μm, median cells 25–38 μm × 20–25 μm, basal cells 38–50 μm × 25–33 μm; cell walls hyaline, with small trigones and without intermediate thickenings. Cuticle smooth. Oil bodies not seen. Leaf lobules rarely reduced, (0.20) 0.35–0.40 mm × 0.15–0.20 mm, to 1/3–1/2 the length of the lobe, at an angle of about 90° to the stem, ovate, inflated along the keel; apex obliquely truncate; keel curved; free margin flat; first tooth 25–38 μm long, oblong, somewhat erect, apex obtuse, sometimes with a second blunt tooth; margin between tooth and sinus 3 cells long; large rectangular disc cell present, cell below the first tooth 45–50 μm long × 18–25 μm wide. Underleaves (0.2) 0.35–0.40 mm × (0.4) 0.55–0.75 mm, to (3) 5 times wider than the stem, contiguous to imbricate, reniform (wider than long); covering the leaf lobules; bilobed, lobes to 1/3–1/4 of underleaf length, about 15–17 cells wide, triangular; sinus broad, acute to obtuse, U-shaped; tips acute to obtuse; underleaf margin slightly crenulate; two large basal underleaf cells lacking; base ± cuneate, insertion line curved. Gynoecia on short or long branches, female bracts crowded, with one innovation, 1–2 gynoecia in a lateral position. Female bracts slightly smaller than the leaf, erect-spreading when moist, not enveloping the perianth. Lobes 0.8–0.9 mm × 0.55–0.60 mm, ovate, apex obtuse, margin slightly crenulate. Lobules 0.5–0.6 mm × 0.20–0.25 mm, rarely reduced, 1/3 the width and 2/3 the length of the lobe, oblong, apex obtuse; keels straight, smooth, 0.40–0.45 mm long, often winged, 1–3 cells wide and 0.2–0.3 mm long. Female bracteoles 0.6–0.8 mm × 0.5–0.6 mm, 3/5 of the perianth length, ovate with tips acute to obtuse, lobes to 1/7 of female bracteole length, distant, sinus narrow, acute, margin slightly crenulate. Perianths (0.5) 0.8–1.0 mm × 0.45–0.50 mm, emergent to 1/2 of the perianth length, obovate, with 5 keels, the keels often winged, 1–2 cells wide; beak 2–3 cells long; cells of the perianth at the keels bulging on surface; stalk-like elongation sometimes present, 0.3–0.5 mm long. Sporophyte: seta 0.2–0.4 mm long; capsule ca. 0.3 mm in diameter, valves 0.35–0.40 mm × 0.20–0.25 mm, rarely spreading after dehiscence; elaters ca. 0.2–0.3 mm long; spores rectangular to irregular-shaped, 38–50 μm × 20–25 μm. Androecia and vegetative propagation not seen.

Distribution:— Indonesia (Western New Guinea), Papua New Guinea.

Further specimens examined:— INDONESIA. Western New Guinea: Zebra flats, end of Lower Meren Valley, Carstensz Mts. West Irian, CGE M62 (JE). PAPUA NEW GUINEA. Central Highlands: along the road from Kundiawa to Goroka, W. of Watabunga, R.M. Schuster 67-5946 (JE). — Eastern Highlands: Goroka, van Zanten 68-2902/b1 (JE). — Simbu Province: Mondia, 9 km SE of Mt. Wilhelm, A. Mundua 154 (JE).

Discussion:— The distinguishing characters of L. tjibodensis are 1) imbricate and often crisped leaves, 2) the acute to apiculate apex of leaf lobe, 3) stem with 9 epidermal cells, 4) leaf cells with small trigones and without intermediate thickenings, 5) the flat free margin of leaf lobules, 6) reniform underleaves, 7) winged female bracts, and 8) perianth with winged keels. Winged female bracts are characteristic of Microlejeunea Stephani (1888: 61) , and are rare among Asian Lejeunea where it is only known in L. tjibodensis . However, L. tjibodensis is easily separated from Microlejeunea by the absence of ocelli.

Figures

FIGURE 8. Lejeunea tjibodensis (Steph.) G.E.Lee & Heinrichs. A. Part of plant in ventral view. B–C. Leaves. D–E. Underleaves. F–G. Underleaves (branch leaves). H,K. Cross-section of stem. I. Stem portion and leaf lobule. J. Female bracts and bracteole. L. Apical cells of leaf lobe. M–N. Upper part of leaf lobules (hyaline papilla shown in gray). O. Median cells of leaf lobe. P. Upper part of perianth. Q. Perianth. R. Perianth with female bracts and bracteole. All figures drawn from the lectotype, Nyman s.n. (G).