Acrolejeunea tjibodensis (Verd.) Grolle & Gradstein

Pócs, Tamás, 2023, New records for the liverwort and hornwort flora of Vietnam 2. Bazzania Gray and some other collections of Pierre Tixier in the National Museum of Natural History, France, Cryptogamie, Bryologie 20 (9), pp. 197-210 : 204

* Acrolejeunea tjibodensis (Verd.) Grolle & Gradstein

( Fig. 5A, B )

SPECIMEN EXAMINED. — Vietnam. Tuyên Duc (now Lâm Đồng), Mt. Lang Bian , épiphyte en forêt dense, intermixed among Bazzania tridens and Lepidozia quadridens, 1900 m , Tixier 278 p.p. ( PC [ PC0764724 ]).

NOTES

Relatively large, yellowish brown plants with about one millimiter wide main stem and Lejeunea type branching. Stem 100-140 µm thick, the brownish unistratose cortex with cells wider than the medullary ones. Ventral merophytes 4-6, more yellow pigmented than the rest. Leaves densely imbricate, undulate and convolute when dry, wrapping around the stem. In wet stage suborbicular, 0.7-0.9 mm long and 0.6 mm wide, with ventrally incurved apex and auriculate dorsal base. When the leaf flattened, the sinus between lobule keel and dorsal margin around 140°. Lobule about º⁄5 of the lobe length, subrectangular, tapering to the truncate apex with two teeth. Underleaves imbricate, elliptic kidney shaped to suborbicular, twice as wide as long, with narrowly recurved margin. They are about five times wider than the stem, approaching in size the side leaves. Gynoecia on the tip of short side branches. The inner bracts are 1-1.12 mm long and 0.64 mm wide, with recurved apex and a lobule of ⅔-¾ length. The innermost bracteole narrow oblong, with rounded and recurved apical part, reaching about two third of perianth length. The perianth 1.1-1.2 mm long, obpyriform, in our specimen with ten smooth or slightly wavy keels and a short beak of 2-3 cells long. Sporophyte on a 15 mm long, articulate seta, capsule valves widely spreading, 400 µm long, light brown, elaters 240-260 µm long with monospiral thickenings. Rare Malesian species, known from Sumatra, Java, Peninsular Malaysia and from West Irian ( Gradstein 1975). New to Vietnam.

Figures

FIG. 5. — Acrolejeunea tjibodensis Grolle & Gradstein:A, habit,ventral view;B, gynoecia, with perianth. Denotarisia ligulifolia (De Not.) Grolle:C, Habit, ventral and lateral view;D, leaf cells.Lepidozia quadridens (Nees) Gottsche et al.: E, habit,ventral view;F, underleaves.Scale bars:A-C,1 mm;D, 50 µm;E, 250 µm;F,100 µm.