Named after Matteo Bazzani (1674–1749), professor of anatomy at the University and Academy of Science at Bologna.

Plants anisophyllous or in some species ± isophyllous, prostrate, rarely sub-erect to erect, forming interwoven wefts or mats. Shoots usually with terminal branches, branching pseudodichotomous (rarely pseudolateral), branches of Frullania type, antidromous; dorsal half-leaf narrowly to widely ovate, tapering to an acute apex, very rarely bilobed. Geotropic microphyllous ventral-intercalary branches present, arising in the axils of underleaves; leafy ventral-intercalary branches sometimes also present, bent horizontally from the point of origin. Leaves on stems, terminal branches and leafy ventral-intercalary branches in two lateral rows and one ventral row (underleaves). Lateral leaves incubously inserted, contiguous to imbricate, opposite to subopposite, weakly to strongly 2–3 (–4)-lobed, rarely entire, occasionally with an extra lobe on some leaves, margins usually entire, sometimes dentate. Underleaves smaller (usually much smaller) than the lateral leaves and very different in shape, appressed to patent, sometimes ± squarrose. Leaf surface usually smooth; in some species striate, papillose or rimose. Mid-laminal cells of lateral leaves shortly hexagonal to isodiametric, becoming ± quadrate at the margins and in the apex, usually longer in the leaf base, trigones minute to very large and bulging; vitta of larger cells lacking chlorophyll sometimes present. Oil bodies usually several per cell, spherical to ellipsoid, colourless, homogeneous, usually larger and fewer in vitta. Cells in underleaves usually similar but smaller to mid-laminal cells of lateral leaves; margin of thin-walled to moderately thick-walled hyaline cells often present.

Dioicous. Plants usually sterile, sporophytes rare. Androecia on short ventral-intercalary branches, also occasionally lateral-intercalary or ventral-intercalary on microphyllous branches, spicate; antheridia 1 or 2 per bract, stalk biseriate. Gynoecia positions as for androecia; gynoecial bracts and bracteoles usually joined at the base, ensheathing the perianth, usually ovate-oblong with an entire to lobed or sometimes ciliate apex. Perianth elongate, terete in the lower half, narrowed and plicate in the upper half, mouth usually lobed, dentate or ciliate. Capsules ellipsoid, black; spores spherical, finely papillose to ruminate; elaters bispiral.

A common and distinctive genus. Smaller species of Bazzania with bilobed leaves are somewhat similar to Acromstigum. However, in Bazzania species with bilobed leaves the lobes tend to be similar in size, whereas in Acromastigum the ventral lobe is usually distinctly larger. Acromastigum species can be readily distinguished from Bazzania by the production of Acromastigum-type branches and by the presence of a distinct stem hyalodermis. Scale-like leaves on the flagelliform branches are rarely bifid in Bazzania but typically so in Acromastigum.

Bazzania includes c. 360 species worldwide, of which 34 occur in Australia and 11 are endemic.

Bazzania Gray, Nat. Arr. Brit. Pl. 1: 704 (1821), nom. et orth. cons. Type: Bazzania trilobata (L.) Gray.

Bazzania echinata (Gottsche) Trevis., listed for Australia (Tas.) by McCarthy (2003), is a nomenclatural synonym of Acromastigum echinatum (Gottsche) A.Evans and may be a synonym of Acromastigum inaequilaterum (Lehm. & Lindenb.) A.Evans. Neither species is recognised for Australia (Brown and Renner, 2014).

Bazzania serpentina (Sande Lac.) Trevis. was listed for Australia (Tas.) by McCarthy (2003) following Meagher (2002). However, Meagher (2015) refers these records to Bazzania wooroonooran Meagher.

Bazzania tridens (Reinw., Blume et Nees) Trevis. was listed for Australia (Tas.) by McCarthy (2003) following Meagher (2002). However, Meagher (2019) made no mention of this species.

Brown, E.A., & Renner, M.A. (2014). The genus Acromastigum in Australia. Telopea 17: 251–293.

Engel, J.J. & Glenny, D. (2008). A Flora of the Liverworts and Hornworts of New Zealand. Volume 1. (Missouri Botanical Garden Press: St Louis, U.S.A.).

Fulford, M. (1959). Studies on American Hepaticae. 7. A supplement to “The genus Bazzania in Central and South America”. II. Tridentatae (1 & 2). Bull. Torrey Bot. Club 86: 315–341.

Meagher, D. (2002). New bryophyte records for Australia. Australian Bryological Newsletter 46: 6.

Meagher, D. (2015). Studies on Bazzania (Marchantiophyta: Lepidoziaceae) 8. Bazzania wooroonooran sp. nov. and seven other rare species from tropical Australia. Nova Hedwigia 100: 535–552.

Meagher, D.A. (2019). A synopsis of the genus Bazzania (Marchantiophyta: Lepidoziaceae) in Australia. Australian Systematic Botany 32: 310–362.

Published October 2020.