Eriosyce laui

Rimacactus laui is a cactus species characterized by its spherical to elongated shoots, measuring up to 3 cm in diameter. These shoots exhibit a whitish-green to reddish coloration and possess a carrot-shaped taproot. The plant's barely visible ribs are segmented into warty tubercles, each bearing a small leaf remnant. The radial spines, numbering nine to thirteen, are thin, needle-like, spreading, and translucent white. They are up to 9 mm long and brittle, with no distinction between central and radial spines. The flowers are narrowly funnel-shaped, approximately 2 cm long and 1.5 cm in diameter, and sulfur-yellow with a whitish-yellow base. They often appear in clusters of up to six. The pericarpel of the flower is smooth or nearly smooth. The fruits are red, elongated, balloon-shaped, and smooth, reaching up to 3.5 cm in length. They open via a basal pore.

Rimacactus laui is native to the north of the Chilean Antofagasta region, specifically near Tocopilla, where it grows on dry slopes of the coastal mountain range with fog at elevations around 400 meters. Plants are found growing along Eriosyce iquiquensis and Eulychnia iquiquensis.