Thalli rather small, prostrate, creeping, in 2 or 3 loosely to quite densely overlying layers forming intricate mats, bottom layer in patches or strips firmly adherent to substrate. bright green when fresh, margins turning translucent as chloroplasts disappear; when dry. duller green. Main axis up to 13 or 14 mm long, generally retaining its dominance, width, particularly in male plants, not uniform, 500-800 µm wide, alternately widening before branching and narrowing again afterwards, segments wedge-shaped, dorsally plane, branching pinnate or occasionally bipinnate, not always equally well developed on both sides, sometimes distally trifurcate or subpalmate, occasionally with lateral incipient branches, apically shallowly notched medianly, adjacent cells meristematic, margins winged; ultimate segment often linear, 575-875 x 285-500 µm. Primary branches lateral, opposite or subopposite, 350-650 µm between pinnae, spreading obliquely at angles of less than 45° with axis, up to 1800 µm long, 375-525 µm wide, secondary branches/pinnules quite rare, rather weak and occasionally just lateral swellings on primary branches, 375-500 x 275-375 µm. Stolons sometimes developing laterally from main axis or from base of primary branches, up to 1375 x 100-140 µm. Dorsal epidermal cells in median part of apical segment of main axis 5-7-sided, thin-walled, 40.0-67.5 x 25.0-37.5 µm, subdorsal cells larger, 4-6-sided, 92.5-135.0 x 30.0-37.5 µm, ventral epidermal cells 42.5-65.0 x 25-35 µm. Oil bodies present in most dorsal and ventral epidermal cells, 10-14 x 7.5-10.0 µm, and in internal cells, where larger, 12.5-22.5 x 12-15 µm, also in ± 20% of marginal cells, but more common in intra-marginal cells, 1 or 2 per cell, and if 2, one smaller than the other, lying close together, subspherical, ellipsoid or ovoid, ends rounded or acute, light brown, finely granular. Margins of ultimate pinnules entire to slightly crenulate, outer cells smaller than intra-marginal ones, sub-quadrate to rectangular, 22.5-40.0 x 17.5-35.0 µm, intra-marginal cells 4-6-sided, 37.5-55.0 x 27.5-32.5 µm, mostly parallel to margin, not in diverging rows. Cross sections of main axis: at ± middle of ultimate segment plano-convex, ± 300 µm wide, 60-90 µm or 3 cell rows thick medianly, tapering laterally to stratose margins, ± 90 µm or 3 cells wide, dorsal epidermal cells ± rectangular, 15-20 µm thick, internal cells few, ± 25 µm thick, ventral cells 10-20 µm thick; at upper portion plano-convex, ± 500 µm wide, ± 90 µm or 4 cell rows thick medianly, tapering to unistratose margins, ± 45 µm or 2 cells wide; at lower portion slightly concavo-convex, ± 520 µm wide, ± 60 µm or 3 cell rows thick medianly, tapering to unistratose margins, 2 or 3 cells or up to 105 µm wide; primary branch ± 60 µm or 3 cell rows thick medianly, unistratose margins 2 or 3 cells wide. Mucilage papillae ventral, clustered at shallow apical notch of branches. 27.5-45.0 x 10-15 µm above, lower down ± 7.5 µm wide, thicker walled above, club shaped, soon becoming spaced in 2 acropetal rows one on either side of midline, not persistent Rhizoids ventral on axes, sometimes in submarginal strips, elsewhere in patches, 12.5 µm wide, occasionally the tips several times branched. Asexual reproduction by gemmae observed in cultured plants, on dorsal surface of upper branches, each of the 2 cells 22.5-2-.0 x 30 µm, joined together at their flat basal wall, the outer walls semi-circular. Dioicous. Male plants up to 8.5 mm long. Antheridial branches along main axes obliquely lateral, opposite or subopposite one another, or opposite a primary branch, otherwise without an opposite pinna, rarely 2 male branches close together, nearly adjoining basally, occasionally male branch near base of primary pinna oblong-linear. 300-750 µm long, mostly stipitate, up to 275 µm wide, bearing 4 or 5(6) pairs of antheridia cavities ± 60 x 85 µm, separated by single mm of cells, 45-50 x 40-50 µm, sometimes basally winged on one or both sides, wing up to 3 cell rows wide, below merging with axis wing, branch in cross section ± 190 µm high, marginal cells erect enlarged, from side (50-)60-70 x 30-40 µm. Gynoecial branches solitary arising laterally along axis, subopposite primary branch or without opposite branching close by, otherwise below primary branch, near base of axis youngest branches rounded.190-250 x 250-260 µm, including paraphyses, unfertilized branches elongating up to 400 µm and with up to6 pans of archegonia paraphyses along both margins. Some with single strands of cells, 37.5-50.0 x 25-30 µm, joined together end to end, others with 2-5 rows of laterally fused cells, 52-125 µm wide, ± arching over archegonia. Calyptra clavate, at maturity 1875-2250 x 425-500 µm above, slightly narrowing below, cross section of wall up to 130 µm or 4 cell layers thick, outermost row with scattered, single-celled papillae, extending upwards to apex, where grouped together to form a corona, cells 125.0 x 32.5-40.0 µm. Seta up to 11.5 x 130-150 µm, with 4 inner and 12 outer cell rows, i.e. 4 cells diam. Capsule ± ellipsoidal, valves 640-730 x 200-350 µm or 16-19 cells wide, bistratose: Cells of epidermal layer in external longitudinal view 55.0-112.5 x 10-20 µm, end walls straight or oblique, with vertical (radial) thickenings, evident as nodular brown bulges along radial walls; inner cells 85.0-162.5 x 10-15 µm, without nodular thickenings, but those on epidermal wall still visible through thin wall; in cross section, cells in epidermal layer ± 10 µm thick, thickenings on adaxial radial and abaxial radial walls extending slightly onto outer and inner tangential walls, bands on 2 sides of median wall alternating with each other in a mirror image; inner cells ± 5 µm thick, with faint ill-defined bands. 12.5-16.0 µm diam., globose, exine layer ± smooth. Elaters 200-275 x 10 µm, with spiral band ± 10 µm wide, tapering to unspiralled apices.
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