Southbyaceae

Terrestrial, lithophytic (not in Victoria) or rarely epiphytic (not in Victoria), dioicous or rarely paroecious (not in Victoria). Asexual reproduction by gemmae produced from leaf surface (not in Victoria) or by short caducous bud-like branches. Stems creeping, not branching, or irregularly or sparingly branched, with two ranks of lateral leaves and without underleaves; branches when present emerging from stems from near lateral leaves and with a collar of tissue at base. Lateral leaves succubous, opposite, narrowly connate, imbricate to distant, ovate to orbicular, obovate (not in Victoria) or reniform, plane (not in Victoria) or concave adaxially, unlobed, entire, rounded at apex. Leaf cells polygonal and isodiametric away from margins, usually becoming more elongate towards acroscopic margin and quadrate or oblate at basiscopic margin, smooth or papillose, thin-walled, without or with (not in Victoria) distinct trigones, with 2–13 oil bodies; oil bodies spherical to ovoid, colourless or yellow (not in Victoria), homogenous or rarely finely granular (not in Victoria). Rhizoids in fascicles or scattered (not in Victoria) on abaxial stem, hyaline or purplish, without peg-like internal thickenings. Androecia on main stem, with 2–6 pairs of leaf-like bracts, each with 1–5 antheridia. Sporophyte at apex of leading stem, surrounded by a pendent marsupium with or without a vestigial perianth, or a low perigynium (not in Victoria) often surmounting a reduced marsupium and with a distinct perianth attached to the perigynium; marsupium cylindric, becoming subterranean, covered in rhizoids or glabrous (not in Victoria), or if forming a perigynium (not in Victoria), marsupium conic with rhizoids; perigynium when present (not in Victoria) ring-like or vestigial; perianth when well-developed (not in Victoria) ovoid, bilabiate, laterally compressed and with entire, crenulate or denticulate margins, or when vestigial, cylindric, bilabiate and with denticulate margins. Capsule cylindric, ellipsoid (not in Victoria), or globose (not in Victoria), bistratose, dehiscing by 4 valves; elaters present, bispiral. Spores papillose (not in Victoria) or finely granulate.