Lejeunea streimannii (Lejeuneaceae, Marchantiophyta), a remarkable new species with robust stems and 5(or 6)-keeled perianths from Papua New Guinea

Lejeunea streimannii , a new species from Papua New Guinea, is described and illustrated. The new species is characterized by the dioicous plants, robust stem with 18 ‒ 21 rows of cortical cells and a ventral merophyte 4 ‒ 6 cells wide, ovate leaves with a rounded, strongly incurved leaf apex, small lobules with unicelluar first tooth and blunt second tooth, large underleaves with a cordate base, inflated perianths with 5(or 6) crenate, slightly winged keels.