Bacopa monnieri
(L.) Wettst.Prostrate perennial, glabrous (except for minute hairs on some sepals). Stems creeping or floating, rooting at nodes, succulent, glossy, often forming dense mats. Leaves sessile, often ± succulent, cuneate-oblong or obovate, 5–13 mm long, 3–6 mm wide, punctate-glandular, apex rounded, base attenuate, margins entire, palmately 3-nerved, the midvein evident but the 2-4 lateral veins obscure. Pedicels 5–8 mm long in flower, lengthening to 23 mm long in fruit. Bracteoles 2, linear, 2–4 mm long, herbaceous. Sepals 3–5.5 mm long, outer 3 ovate and 2.3–4.2 mm wide, herbaceous except for lower margin of one of the two lower sepals which is stramineous and minutely ciliate along margin, glandular-punctate, veined, the 2 inner ones c. 1 mm wide, not glandular-punctate, minutely ciliate along margin, herbaceous becoming stramineous, keeled, the keel crenate-dentate near base. Corolla 5–10 mm long; tube 2–4.5 mm long, white in the upper ½ and greenish yellow or yellow in lower ½; lobes white or very pale blue, spreading, rounded, apex emarginate. Stamens didymous. Capsule (mature capsules not seen in Victorian plants) ovoid or ellipsoid, c. 4 mm long, topped by persistent style 3–4.5 mm long. Dec.-May. (based on Victorian records in iNaturalist).
Native to Qld and NSW (north from Royal National Park). Naturalised in WA and SA. Also native to most of Africa, North and South America, parts of western and southern Asia, Madagascar. .
In Victoria, known from two recent (2026) collections from Waterways, and Caversham Waters Wetlands in Pakenham where growing in constructed wetlands. At the Pakenham location it is prolific, dominating large sections of the wetlands. There is also an iNaturalist observation from a constructed wetland at Keysborough where not found when inspected by the author (March 2026), and a 2019 observation from Main Ridge with no context provided by the observer other than the plants were self-established. The invasive propensity of this species is clear at Pakenham and it has the potential to spread further (e.g. by birds) becoming a serious environmental weed of some Victorian wetlands. The species is sold at several Victorian nurseries and is available for purchase online.
Barker, W.R. (1992). Scrophulariaceae, in Harden, G.J. (ed.), Flora of New South Wales 3: 552–590. (New South Wales University Press: Kensington). See also New South Wales Flora Online: https://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Bacopa~monnieri [Accessed 26 March 2026]
Hong, D., Yang, H., Jin, C-li., Fischer, M.A., Holmgren, & Mill, R.R. (2000). Scrophulariaceae, in Zhengui, W.. (ed.), Flora of China 18: 1–203 (Science Press: Beijing, and Missouri Botanic Gardens Press: St Louis); eFlora http://www.efloras.org/florataxon.aspx?flora_id=2&taxon_id=200020622 [Accessed 26 March 2026]
'WFO (2026): Bacopa monnieri (L.) Wettst. Published on the Internet;
http://www.worldfloraonline.org/taxon/wfo-0000558282 [Accessed on: 26 Mar 2026]