VicFlora: Opuntia bonaerensis

Erect shrub to 3(–4) m high, occasionally with a small trunk, plants to 5 metres diam. Terminal cladodes compressed, narrowly obovate to obovate or elliptic, 9–32 cm long, 4–14 cm wide, 20–28 (–40) mm thick, glabrous, green and glossy, often tinged reddish purple along the cladode margin and around areoles; areoles 12–32 per cladode face, c. 18–55 mm apart, with reddish-brown glochids; spines absent or 1 (rarely 2) per areole on 1 (rarely several) areoles, erect or variously spreading, 7–48 mm long, 0.7–1.2 mm wide near base, slightly curved towards apex, dark red-brown or reddish-purple with yellowish apex, ageing greyish-brown or pale grey. Early flower bud with an acute apex. Flowers (3.5–)6–9.5 cm diam.; sepaloids distinctly crimson tinged; petaloids spreading or somewhat erect, orange, the outer ones reddish-tinged mostly toward the apex; stamens yellow; style pale yellow, stigmas green; hypanthium smooth, dull. Fruit obovoid, shallowly depressed at apex, 6–8 cm long, 2–2.5 cm diam., smooth, spineless, dull, carmine at maturity (including pulp), deciduous, juicy. Flowers late spring–summer.

MuM. MuM, VVP, MSB, RobP, MuF, OtP, Gold, CVU. Also SA, Qld, NSW, ACT. Native to Brazil (Rio Grande do Sul) to NE. Argentina.

Locally common in far north-western Victoria (e.g. roadsides near Ouyen) and along the Murray River near Red Cliffs, noted also in bushland and along rail-lines near Bacchus Marsh, Werribee and Geelong.

At various points in time, the plants in Australia have been referred to as Opuntia paraguayensis, O. cardiosperma, and more recently O. elata. In a non-exhaustive analysis of floristic works, technical documents and digital pages by Aymerich & Font (2023), the authors argue that it has not been possible to assign Australian plants to O. elata s.s. Aymerich & Font (2023) provide a table of comparative character states of related species, illustrations of the character states in Figure 1, as well as colour images. Based on limited observations (by V. Stajsic) of the plants naturalised in south-eastern Australia, herbarium specimens, and a review of some of the available images (available up to 2023), the plants appeared to be consistent with the diagnostic characters for O. bonaerensis Speg. as given in Aymerich & Font (2023). The authors claimed that their work showed that O. bonaerensis is the most widespread species from ser. Armatae, perhaps the only one from that series, naturalised in Australia, where it is currently treated as O. elata. However, in 2025 Fabian Font identified an iNaturalist observation (uploaded on 27 Feb 2025) of Opuntia elata s.s. from near Corowa in NSW (close to the Victorian border), confirming that both O. bonaerensis and O. elata are present in Australia, O. elata being a lot rarer. Aymerich & Font (2023) provide several characters that aid in differentiating between O. bonaerensis and O. elata, of which early flower bud apex shape, the colour of stigma lobes and pulp colour appear to be more practical differences. O. bonaerensis has an acute flower bud apex, green stigma lobes, and carmine pulp, whereas O. elata has a rounded, obtuse flower bud apex, creamy stigma lobes, and green pulp.