Frullania pentapleura

Lithophytic or epiphytic, olive-green to reddish brown. Stems irregularly pinnate or bipinnately branched. Mid stem and branch lateral leaf lobes ovate to suborbicular, (0.35–) 0.45–1.2 mm long, 0.3–1 mm wide, with rounded to obtuse apex, sometimes angled away from substrate but not squarrose away from substrate when moist, remote to imbricate; cells elliptic, circular or irregular, 8–20 µm long and 8–15 µm wide at margins, 8–30 µm long and 8–24 µm wide near centre, 20–43 µm long and 15–35 µm wide at base, with trigones throughout and occasional intermediate thickenings mostly away from margins and base or intermediate thickenings absent. Lobule galeate, oblate to c. as wide as tall, 0.13–0.4 mm wide, 0.18–0.4 mm tall, rounded at apex; cells rectangular to irregular, 12–25 µm long, 7–18 µm wide. Stylus (3–) 4–6 (–7) cells, 1–2 (–3) cells wide at base, usually with a single row of 2–4 cells at apex. Underleaves suborbicular to cuneate in outline, bifid 1/3–1/2 of length, otherwise entire or with a single blunt tooth at shoulders, (0.18–) 0.19–0.51 mm long, (0.15–) 0.18–0.55 mm wide, flat, distant; sinus obtuse or acute; cells elliptic to irregular, 12–30 µm long, 8–23 µm wide. Perianth pyriform or obovoid, 5–9-keeled, (0.75–) 0.9–1.35 (–1.5) mm long, (0.6–) 0.7–1 (1.2) mm wide, truncate at apex, with small beak, smooth; keels acute.