Pereskia nemorosa, synonym Rhodocactus nemorosus, is a species of flowering plant in the cactus family Cactaceae, native to southern Brazil, Paraguay, Uruguay and northeast Argentina. Like all species in the genus Pereskia and unlike most cacti, it has persistent leaves. It was first described by Nicolás Rojas Acosta in 1897.
Description Pereskia nemorosa grows as a small tree or a shrub, reaching high, with trunks to in diameter. Mature stems develop bark and, unlike other species of Pereskia, do not have stomata. Like all species of Pereskia and unlike most other cacti, P. nemorosa has persistent leaves, the largest being up to long and wide. The leaves are succulent and have short petioles, only long, and are borne on the areoles along with spines. The areoles on the twigs have up to five spines, those on the trunks up to 20 or more, each long. The white to pale pink flowers are either solitary or borne in small terminal inflorescences of two to five, and are across. The fruits are pear-shaped, green or yellowish-green when ripe.
Taxonomy The species was first described by Nicolás Rojas Acosta in 1897. Molecular phylogenetic studies suggested that when broadly circumscribed, Pereskia was not monophyletic, and consisted of three clades. In 2016, the genus Rhodocactus was revived for one of these clades, which included R. nemorosus. In 2025, a major study of the phylogenomics and classification of cacti by De Vos et al. did not recognize Rhodocactus, based on sparse taxon sampling. , Plants of the World Online agreed, accepting Rhodocactus nemorosus as a synonym of Pereskia nemorosa.
Distribution and habitat Pereskia nemorosa is native to southern Brazil, Paraguay, Uruguay and northeast Argentina. It is found in drier wooded habitats.
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