Lejeunea helmsiana

Yellow-green patches on fern fronds, monoicous. Specialised asexual propagules absent. Leaves broadly ovate, 410–975 μm long, 400–800 μm wide, imbricate, rounded to obtuse at apex, directed slightly in direction of stem apex, entire, lobe extending to opposite edge of stem dorsally and completely obscuring stem from above; lobule broadly ovoid, 250–325 μm long, 140–340 μm wide, slightly inflated, with tooth furthest from stem directed parallel to stem or curving slightly away from stem, on most leaves formed by a single row of 2–3 non-elongated cells, sometimes tooth unicellular, with a slightly to distinctly outwardly bulging keel that ends in a notch formed by adjoining lobe margin descending in direction of stem base below level of keel apex. Underleaf orbicular in outline, bilobed, 200–475 μm long, 225–515 μm wide, remote; lobes 0.45–0.55 the length of underleaf, separated by a V-shaped sinus with obtuse to rounded base and straight edged sides, acute to bluntly pointed at apex. Leaf cells away from margin polygonal, 23–43 μm long, 16–33 μm wide, smaller at margin where quadrate to rectangular and 12–23 μm long, 12–15 μm wide, thin-walled, without or with rare and obscure intermediate thickenings, without or with small trigones, smooth.