Plants small (main shoots 300–500 μm wide), typically olive-green to occasionally copperbrown, and closely to loosely adhering to substrate. Leading stem to 10 mm long and to 50 μm in diameter (without leaves), 5–6(–7) cells wide, little differentiation between cortical cells (12–16 in no.) and medullary cells (7–10 in no.), former slightly smaller than the latter, both with firm walls, lumen irregularly shaped. Branching often irregularly to occasionally regularly pinnate. Dimorphic branching, with both Frullania-type (FB) and occasionally, Lejeunea-type (LB) branching. Initial appendages of FB: First branch underleaf (BUL1) always with three distinct segments, the ventral lamina divided for ca ½ its length into two subequally sized lobes + 1 dorsal lobe which is usually saccate, or occasionally sulcate to explanate. First branch leaf (BL1) varies, either: reduced in size, ventral segment elobulate, and explanate to sulcate, with leaves characteristic of the main stem starting at BL2–BL3(–BL4); or the appendages of BL1 ± characteristic of normal stem leaves (i.e. BL1: 1 explanate dorsal lobe + 1 saccate lobule + 1 stylus). Initial appendages of LB: BUL1 and BL1–BL3 are always reduced in size and lobule-free, formation of normal lobulate leaves occurring thereafter. Stem leaves of main branch flat when dry and wet, slightly imbricate to contiguous, suborbicular to broadly oval, to 275 μm long × 175 μm wide with incurved distal margins, and dorsal margins extending beyond the farther edge of the stem, rounded to subacute apices and non-auriculate at the base, margins entire and smooth dorsal surface. Lobules ± remote from the stem (lobule attached to stem by 3–4 cells) and at angles of 40–50° with the stem so that lobules tilted outwards; lobules similar in colour to other organs; cylindrically pitcher-shaped (orbicular in cross-section with up to 24 cells in circumference) and ca 1.5–2 × long as wide, lobules large (its area obscuring at least 1/3 × the exposed area of the dorsal lobe), 110–150 μm long × 60–80 μm wide; somewhat dorsiventrally compressed near mouth as compared to gibbous upper third, the opening wide, extending along the abaxial lobule margin; ca 1/3 from lobule mouth there is usually a ± enlarged and elongated, gibbous, slightly protuberant cell; free margin of lobular mouth crenulate-sinuate, especially near the sinus, usually hyaline near mouth, lobule apex obtuse. Stylus, triangular, ± large (1/2–2/3 the length of the lobule), 50–75 μm long × 30–40 μm wide, 5–7 cells wide × 5–9 cells high (15–25 cells in total), rarely with a slime papilla at apex. Underleaves of leading stems, contiguous or just overlapping with lobules, underleaves contiguous to distant from each other, small (ca 0.25 × the size of leaf lobes), (1.00–)1.25–1.50(–2.00) × the stem in width, underleaf usually as long as wide, occasionally slightly wider than long, 80–110 μm long × 65–85 μm wide, broadest at middle (8–11 cells wide); entire lateral margins; apex of underleaf bilobed to 1/2 its length, lobes separated by a narrowly U to V shaped sinus; each lobe with 4–5 cells at the base, lobes with acute to subacute apices. Rhizoid-initial area present near base of underleaf, rhizoids occasionally seen, subhyaline, in short bundles. Microphyllous branching absent, or with pseudo-microphyllous branches where the lobules of secondary stems ± similar size to main stem, but lobes and underleaves of secondary branches markedly smaller than those of leading stems. Underleaves of secondary branches usually with a V-shaped sinus separating the underleaf lobes, and only 2–3 cells wide at the base of each lobe. Lobe marginal cells ± rectangular, hyaline walls subequally thickened, cell cavities brownish red, to 7–9 μm long × 7–9 μm wide; median cells ± subquadrate, rectangular, or 5-sided; hyaline walls subequally thickened, intermediate thickening rare to absent, wall thickness to 2 μm wide (without intermediate thickenings), cell cavities of median cells brownish red, 8–12 μm long × 8–10 μm wide; cells becoming gradually larger basally, cavities of the basal median group of cells to 14–18 μm long × 12–16 μm wide; walls of basal cells with subnodulose trigones and occasional intermediate thickenings, walls and cavities brownish red. Median cells of underleaves often with small, hyaline, trigones with no intermediate thickening or with subequally thickened walls so that the trigones become indistinct from the longer walls, cell cavities to 12 μm long × 12 μm wide. Median cells of lobule slightly longer than wide, cell cavities 1.5–2 × long as wide, to 12 μm long × 7 μm wide, walls flexuose with indistinct trigones and small nodulose intermediate thickenings. Oil-bodies of the leaf lobe median cells 2–3 (–4) per cell, typically small, spherical (1–)2–3(–4) μm in diam. to ovoid or ellipsoidal (2–)2–3(–4) × (1–)1–2(–3) μm, subhyaline, without any significant, visible, internal structure i.e. giving the appearance of being almost homogeneous. The oilbodies are often similar in size or slightly smaller than the chloroplasts; occasionally the oilbodies are larger than the chloroplasts. The oil-bodies of the lobule and underleaf are similar to those encountered in the leaf lobe. Oil-bodies becoming progressively larger towards the basal cells: usually 3–5 per cell, to 7 μm × 5 μm, coarsely granular, ocelli never present. Asexual reproduction not known.
Monoicous (often with the androecium directly posterior to the female bracts or with androecial branches a short distance below the female inflorescence). Androecia subspherical to discoid, 150 μm long × 150 μm wide, usually with 2 pairs of closely imbricate bracts, sessile on leafless stalks or terminal on very short-stalked branches [stalk with 1–2(–4) vegetative leaf lobes]. Gynoecia terminal on main or leading stem. A shoot system often occurring between bracts and perianth (subfloral innovation) or arising 2 complete leaf cycles below the gynoecia or perianth bracts i.e. a subfloral branch. Female bracts and bracteoles usually only in 2 pairs. Innermost bract unequally bilobed; bract-lobe lanceolate-elliptical to obovate, to ca 300 μm long × 150 μm wide, gradually narrowed toward an acute, blunt or obtuse apex, margin entire except 2–3 small teeth at the base; bract-lobule, triangular, to ca 250 μm long × 125 μm wide, with an acute to subacute apex, on free margins with a single small angulation or tooth near the base; innermost bracteole free from bracts, oblong to obovate, to ca 250 μm long × 175 μm wide, about 1/3–½ bilobed, the sinus narrowed, lobes with convex sides, triangular, acute at apex, with entire margins. Marginal cells of bract and bracteole ± subequally thickened, but towards the median cells, trigones becoming large and bulging. One archegonium per gynoecium. Perianth partially exserted to freely emergent, 400–600 μm long (beak omitted) × 225–250 μm wide, with 3 rounded keels + 2–3 supplementary keels, oblong-ovate, tapering towards the apex into a short beak; cells of the perianth surface often each elevated as small, to ca 4 μm high tubercles; perianth beak cylindrical, to 50 μm long, rim of the perianth mouth smooth, but the inner beak surface covered with large single-celled protuberances (to 10 μm long).Capsule valves to 275 μm long × 200 μm wide; elaters (12–)14–20(–22) in total (common arrangement on two alternating valves: 1+3; 2+3, elaters rarely arranged in rows of 3 on the valve); unispiral, to 175 μm long × 15 μm wide, elater surface irregularly rugose-granulate. Epidermal cell layer (7–)8–9 cells at the widest region. Epidermal cells with 4–5 sides, the thickenings at the angles of the epidermal cells extend out as lobes; consequently the juxtaposed thickenings of adjoining corners form a (1–) 2 (–3) unevenly lobed configuration. Inner cell layer: portions of the radial walls are spread irregularly over the free tangential face and are strongly thickened, forming a sinuate partial layer of thickening or jigsaw like pattern. Spores globose, to 43 μm at widest axis, interspersed with 8–10 rosettes; each rosette to 4.5 μm in diam., bearing a ring of 6–8 conspicuous protuberances; these primary projections never papillate or branched, 1–1.51 × as long as wide, 1–1.5 μm long × 0.75–1.00 μm wide at base, gradually tapering to an obtuse or rounded apex; spore wall papillae otherwise densely distributed between regions of the rosettes.