Plagiochasma

Mostly on thin soil over rock, monoicous. Thallus sparingly forked at apex and branching from abaxial thallus away from apex, often forming extensive patches, grey to blue green, yellow-green (not in Victoria) or green (not in Victoria), often becoming violet, black or black-purple at margins, glabrous, without adaxial grooves; margins undulate, becoming incurved when dry. Photosynthetic tissue divided vertically into several irregular tiers of air chambers, thicker than underlying storage tissue; specialised air pores surrounded by 1–4 concentric rings of cells, elevated (not in Victoria) or not above adjacent adaxial thallus. Oil cells present in adaxial epidermis, throughout thallus tissues and in abaxial scales. Abaxial scales triangular, ovate or lunate (not in Victoria), with 1 or 2, rarely up to 4 apical appendages, purplish black to violet, entire or (not in Victoria) with occasional papillae or teeth; appendages obscure and hardly differentiated from rest of scale or (not in Victoria) strongly constricted at base and orbicular to ovate or ovate-lanceolate. Adaxial epidermis cells persistent, with or without (not in Victoria) a granular deposit, hyaline, collenchymatous, unistratose. Androecia sessile circular to crescentic, V-shaped (not in Victoria) or reniform cushions on adaxial thallus, encircled by linear or linear-lanceolate scales. Archegoniophore on adaxial thallus away from margin and growing apex; stalk to c. 7 mm tall, without a rhizoid furrow or air pores, with linear or linear-lanceolate scales at base and apex; carpocephalum 2–6 lobed, flat or slightly depressed; involucre bilabiate; pseudoperianth absent; capsule dehiscence by a decaying lid, unistratose; elaters 2–3-spiral, rarely 4–5-spiral. Spores tetrahedral with prominently winged margins, areolate, yellow to brown; proximal face with triradiate mark.