Species of Oxera show a variety of growth forms, including lianas, shrubs and trees. The leaves are simple, and are petiolate (on short stalks), except in O. sessilifolia, with entire or occasionally sinuate (wavy) edges.
The inflorescences are loose thyrses of flowers, growing from leaf axils (axillary) or directly from the stem (cauliflory). The flowers are large, conspicuous and bisexual; the calyx is actinomorphic (rotationally symmetrical), but the corolla is zygomorphic, sometimes strongly so. Although some species have four stamens in each flower, they are usually reduced in number with two stamens, usually the posterior pair, forming staminodes instead.
^ abcdefR. M. Harley, S. Atkins, A. L. Budantsev, P. D. Cantino, B. J. Conn, R. Grayer, M. M. Harley, R. de Kok, T. Krestovskaja, R. Morales, A. J. Paton, O. Ryding & T. Upson (2004). "Labiatae". In J. W. Kadereit. Flowering plants, Dicotyledons. Lamiales (except Acanthaceae including Avicenniaceae). The Families and Genera of Vascular Plants 7. Springer. pp. 167–275. ISBN978-3-540-40593-1.
^D. J. Mabberley & R. P. J. de Kok (2004). "Labiatae". Hippocrateaceae, Labiatae, Vitaceae. Flore de la Nouvelle-Caledonie et Dependances 25. Association de Botanique Tropicale. pp. 20–141. ISBN978-2-85654-219-4.