Rhodocactus sacharosa

Rhodocactus sacharosa grows as a small tree or a shrub, reaching 5–7 m (16–23 ft) high.[2] Mature stems develop bark and, like most other species of Rhodocactus, have stomata.[3] Like all species of Rhodocactus and unlike most other cacti, R. sacharosa has persistent leaves. These are very variable in shape and size, 3–12 cm (1.2–4.7 in) long and 2–7 cm (0.8–2.8 in) wide, often folded along the midrib, which is very prominent on the underside, and with obvious petioles. The areoles on the twigs have up to five strong spines, 1–4 cm (0.4–1.6 in) long, those on the trunks may have up to 25 spines, 3–3 cm (1.2–1.2 in) long. The flowers are various shades of pink and are either solitary or borne in small terminal inflorescences of two to four, each flower being 3–7 cm (1.2–2.8 in) across. The fleshy fruits are more or less globe-shaped or pear-shaped, 4–5 cm (1.6–2.0 in) long and wide, green or yellowish when ripe.[2]

Spines on a leafless stem

The species was first described by August Grisebach in 1879 as Pereskia sacharosa.[4] The specific epithet sacharosa is a noun in apposition, derived from a vernacular name.[5] One explanation is that it is derived from the Quecha word sacha, meaning 'tree' or 'woods', hence 'tree rose' or 'woods rose'.[6] In 1966, Curt Backeberg transferred the species to the genus Rhodocactus.[4] However, this was not accepted by most botanists, and Rhodocactus was sunk into a broadly circumscribed Pereskia. Molecular phylogenetic studies from 2005 onwards suggested that with this circumscription, Pereskia was not monophyletic, and consisted of three clades.[7][8][3] In 2016, the genus Rhodocactus was revived for one of these clades, which included R. sacharosa.[3]

Rhodocactus sacharosa is native to Bolivia and west-central Brazil southwards to Paraguay and northern Argentina.[1] It occurs at elevations of 1,000–2,500 m (3,300–8,200 ft) in the foothills of the Andes and the semiarid Gran Chaco region.[2]