Yungasocereus

Yungasocereus is a monotypic genus of cactus containing one species, Yungasocereus inquisivensis.

Description

Yungasocereus inquisivensis is a columnar cactus, appearing either as a tree or shrub, ranging up to 4–5 meters in height. The diameter stems are dark green, with 6-10 ribs. The spines are in groups of 4-12, with no differentiation into central and radial types, and range from a brownish to grayish color. The flowers are white, appearing in groups of 5-8 near the stem tips. They open day and night and are long.
The fruits have a length between. They contain small, broadly oval, shiny black, slightly keeled seeds on the back, long and wide.

Taxonomy

Martín Cárdenas described the species in 1957 from Inquisivi, placing it in Samaipaticereus. Friedrich Ritter later found the same species in Yungas. In 1980, he gave the cactus its own genus, Yungasocereus. After a period in Haageocereus, the species was again separated into Yungasocereus. A 2023 molecular phylogenetic study led to Cleistocactus being expanded to include Yungasocereus and Samaipaticereus. The expansion is not accepted by Plants of the World Online as of 2025, with this species accepted as Yungasocactus inquisivensis.

Distribution

Yungasocereus inquisivensis is known only from Yungas and Inquisivi provinces of La Paz Department, where it is found at elevations of around 1000 to 2300 meters.