Plagiochila
Epiphytic, lithophytic or terrestrial (not in Victoria), dioicous. Asexual reproduction by caducous leaves (not in Victoria), marginal leaf cilia (not in Victoria) or branchlets produced on leaf surfaces (not in Victoria). Stems differentiated into creeping stems with reduced leaves that give rise to aerial ascending, erect or pendulous stems with normal leaves, these sparingly to irregularly or pinnately branched or forking, sometimes with paraphyllia (not in Victoria) or lamellae (not in Victoria); branches on aerial stems emerging near unmodified lateral leaves or rarely from abaxial stem in androecia (not in Victoria) and with a collar of tissue at base, or sometimes emerging abaxial to narrower lateral leaves and without a collar of tissue at base. Lateral leaves ovate or reniform-orbicular to oblong, obovate or falcate (not in Victoria), often asymmetric, alternate, rarely opposite (not in Victoria), succubous in insertion and orientation, sometimes transversely or longitudinally (not in Victoria) oriented or rarely secund in direction of abaxial stem (not in Victoria), usually unlobed, rarely 2–3-lobed (not in Victoria), usually with numerous teeth along acroscopic margin and at apex, and entire or dentate and usually revolute along basiscopic margin forming a cnemis, rarely completely entire, rarely conspicuously crispate along margins (not in Victoria), distant to imbricate; lobes when present (not in Victoria) triangular to linear. Underleaves bifid and ciliate (not in Victoria), vestigial and triangular or filiform, or absent. Leaf cells quadrate, polygonal, ovoid, oblong, elliptic or rectangular, sometimes becoming more elongated toward central base or rarely elongate throughout (not in Victoria), smooth, with thin walls and distinct, often confluent trigones, often becoming more evenly thick-walled toward margins, or evenly firm- to thick-walled throughout and without distinct trigones, with 1–40 oil bodies; oil bodies ellipsoid, ovoid or spherical, homogenous, botryoidal or granular, colourless or bluish-brown (not in Victoria). Rhizoids scattered on creeping stems with reduced leaves, or rarely at bases of leaves (not in Victoria) or scattered throughout (not in Victoria) on normal leafy stems. Androecia becoming intercalary, with dentate to entire and highly differentiated saccate or sometimes leaf-like bracts in 2–60 pairs, each with 1–4, rarely up to 10 (not in Victoria) antheridia. Sporophyte terminal on leading axes or short branches, developing within a perianth; perianth ellipsoid or campanulate to obovoid, obloid or cylindric (not in Victoria), usually with an abaxial and adaxial keel, sometimes pronounced as wings, with two-lipped ciliate, dentate, laciniate or rarely entire (not in Victoria) mouth; capsule globose, ovoid or ellipsoid, 4–9-stratose; elaters uni-, bi- or rarely up to 5- (not in Victoria) spiral; spores globose, granulate, sometimes with precocious division inside capsule.
Around 600 species and worldwide but most diverse in the Neotropics, south-east Asia and Malesia (Schuster 1980; Söderström et al. 2016); five species in Victoria.
Plagiochila is the largest genus of liverworts and have been variously divided into sections based on combinations of morphological features such as branching types, perianth form, leaf shape, cell pattern and dentition, and androecium and sporophyte position (see Renner et al. 2017; Schuster 2021). However, even species that share highly unusual morphology in this genus have been found to be unrelated in phylogenies based on DNA sequences and major alterations of sectional boundaries to reflect true relationships have been and will continue to be required (Renner et al. 2017). The majority of Australian species of Plagiochila have been included in molecular phylogenies, confirming a sectional placement for our species (Renner et al. 2017). Three sections occur in Victoria: section Denticulatae (P. fuscella (Hook.f. & Taylor) Taylor & Hook.f. ex Gottsche, Lindenb. & Nees and P. retrospectans Lindenb.), section Belangerianae (P. fasciculata Lindenb. and P. strombifolia Taylor ex Lehm.), and section Deflexifoliae (P. circinalis (Lehm. & Lindenb.) Lehm. & Lindenb.) (Renner et al. 2017; Renner 2018).
Renner, M.A.M., Patzak, S.D.F., Heslewood, M.M., Schäfer-Verwimp, A. & Heinrichs, J. (2017). Third time lucky? Another substantially revised sectional classification for Australian Plagiochila (Plagiochilaceae: Jungermanniopsida). Australian Systematic Botany 30: 70–104.
Renner, M.A.M. (2018). A revision of Australian Plagiochila (Lophocoleinae: Jungermanniopsida). Telopea 21: 187–380.
Schuster, R.M. (1980). The Heapaticae and Anthocerotae of North America, east of the hundredth meridian, volume IV. Columbia University Press: New York.
Schuster, R.M. (2021). Austral Hepaticae Part III. Nova Hedwigia Beiheft 120. Cramer in der Gebrüder Borntraeger Verlagsbuchbehandlung: Stuttgart.
Söderström, L., Hagborg, A., von Konrat, M., Bartholomew-Began, S., Bell, D., Briscoe, L., Brown, E., Cargill, D.C., Costa, D.P., Crandall-Stotler, B.J., Cooper, E.D., Dauphin, G., Engel, J.J., Feldberg, K., Glenny, D., Gradstein, S.R., He, X., Heinrichs, J., Hentschel, J., Ilkiu-Borges, A.L., Katagiri, T., Konstantinova, N.A., Larraín, J., Long, D.G., Nebel, M., Pócs, T., Puche, F., Reiner-Drehwald, E., Renner, M.A.M., Sass-Gyarmati, A., Schäfer-Verwimp, A., Moragues, J.S., Stotler, R.E., Sukkharak, P., Thiers, B.M., Uribe, J., Váňa, J., Villarreal, J.C., Wigginton, M., Zhang, L. & Zhu, R. (2016). World checklist of hornworts and liverworts. Phytokeys 59: 1–828.
Spinning