Asterella

Terrestrial or in thin soil over rock, monoicous or dioicous. Thallus forked at apex and branching from abaxial thallus away from apex, forming dense patches or mats, pale, lime or bright green, often becoming purple at margins, without adaxial grooves; margins undulate, becoming incurved when dry. Photosynthetic tissue with a single tall layer (not in Victoria) or several overlapping short tiers of air chambers, these sometimes further divided into additional partitions not open to adaxial surface; specialised air pores surrounded by 1–4 concentric rings of cells, slightly elevated. Oil cells in adaxial epidermis, photosynthetic tissue, storage tissue and abaxial scales. Abaxial scales in 2 rows, conspicuous, ovate or triangular to lunate, with 1–4 appendages, purple; appendages oblong, linear or ovate to lanceolate, sometimes constricted at base, entire or toothed (not in Victoria). Adaxial epidermis cells persistent, hyaline, thin-walled or collenchymatous. Androecia an indistinctly defined cluster of antheridia near apical notch or reniform to elliptic cushions on adaxial midline of thallus away from apex or at apex and encircled by small scales. Archegoniophore arising from apical notch; stalk to c. 30 mm tall, with or without air chambers, with a single rhizoid furrow, usually with scales at base and apex; carpocephalum obscurely 2–4 lobed, hemispheric, conic or flat, smooth, warty or spiny (not in Victoria), with compound air pores adaxially; involucre bivalved or entire; pseudoperianth present, split to around half way to base into 8–16 free or apical fused segments, projecting beyond capsules or not; capsule dehiscence by a decaying lid, unistratose; elaters 1–3-spiral. Spores tetrahedral with prominently winged margins, areolate, yellow, orange-yellow, brown, purple (not in Victoria), red-brown (not in Victoria) or black (not in Victoria); proximal face with or without (not in Victoria) triradiate mark.