Harrisia tortuosa (J.Forbes) Britton & Rose

Stems sprawling or clambering, to 4 m long, 4–6 cm diam., green. Ribs 6–8, separated by conspicuous line at sulcus, tuberculate. Central spines 1–3, 25–50 mm long, stout, red, ageing almost black. Radial spines 6–9, 10–20 mm long, subulate, pale coloured. Flowers 10–15 cm long, 8–14 cm diam. Pericarpel brownish green, sometimes having areoles similar to stem areoles with spines and without scaly trichomes. Hypanthium pale pinkish green, scales red, ovate, with white hairs, sometimes the lower hypanthium areoles similar to stem areoles with spines and without scaly trichomes. Mid-hypanthium scales 2.0–3.5 mm long, 5.5–7.5 mm wide. Outer tepals pale pinkish green-brown. Inner tepals white. Fruits globose, 2–5 cm diam., tuberculate, red, with or without spines, radial spines c. 5 mm long, scales deciduous.

In Australia, Harrisia tortuosa is found in drier areas such as Acacia harpophylla scrub and open woodland. At Western Creek (southeastern Queensland) it is naturalised in open Eucalyptus woodland with Allocasuarina luehmannii, on sandy clay loam. Near Mount Morgan it grows in grassland, along the road. At Grawin in northern New South Wales it is naturalised in Eucalyptus populnea subsp. bimbil and Callitris woodland, on red sandy soil. At Lightning Ridge it grows in Acacia, Eremophila mitchellii and Geijera parviflora association with a chenopod dominated understorey. The species has apparently also been found in Pinus radiata plantations (https://keys.lucidcentral.org/demo/js_player/sew2/text/harrisia_tortuosa.htm).

Harrisia tortuosa  was introduced into Queensland as a pot plant in the 1890s, and was and was planted by people living near mining towns.