Treubiaceae

Terrestrial, rarely lithophytic or on logs, monoicous (not in Victoria) or dioicous, with both male and female plants similar in size. Asexual reproduction sometimes by ovoid to obovoid gemmae produced in axils of adaxial lobules. Plants comprising a thallus differentiated into a fleshy axis bearing 2 rows of leaf-like segments. Stems unbranched or freely to sparingly branched; branches emerging from main fleshy axis laterally between leaf-like segments or (not in Victoria) furcate at apex. Leaf-like segments divided to near base into an erect small adaxial lobule, near the fleshy axis, and a larger abaxial lobe, yellow- to deep green; abaxial lobe semicircular to oblong-lingulate, spreading parallel and close to substrate, alternate, succubous, contiguous to imbricate, decurrent along axis, entire, rounded or retuse at apex, multistratose except at margin; adaxial lobules crescentic to semicircular, alternate, remote to imbricate, decurrent toward midline of axis, unistratose; lobe cells polygonal, subquadrate near margins, smooth, thin-walled, without trigones. Oil cells comprising a single large granular-botryoidal brown to grey oil body present in epidermal and internal cells of adaxial lobules, abaxial lobes and axes, few or abundant. Abaxial papillae on ridges of leaf and stem excrete copious mucilage. Rhizoids abundant along stem, smooth, colourless. Antheridia scattered on adaxial axis (not in Victoria) or confined to axils of adaxial lobules, sessile (not in Victoria) to long-stalked. Sporophytes on the adaxial axis (not in Victoria) or arising only from axil of adaxial lobules, elevated above axis by shoot calyptra; shoot calyptra clavate, fleshy; involucre absent; pseudoperianth absent. Seta elongated. Capsule cylindric-ellipsoid or globose (not in Victoria), 2–5-stratose, dehiscing by 4 valves; elaters present, bispiral. Spores areolate on distal face, light brown, shed singly.