The spherical to cylindrical, light green to dark-green shoots reach heights of growth of up to 1 meters with a diameter of 1.5-3.0 cm (1.2 in).

The broad, funnel-shaped woolly bud with creamy white flowers appear near the top of the shoot and are open during the day.

The ovoid shiny green fruits are 32 mm (1.3 in) long and 23 cm (9.1 in) in diameter covered with scales.

[2][3] Plants are found growing in the shade in dry woodland forest in alkaline clay soil in Rio Apa, Presidente Hayes Department, Paraguay at elevations of 200 to 500 meters.

[2] This species was first described by Curt Backeberg as Mediocactus hahnianus in 1957 based on a plant found in Hahn's nursery.