This is another columnar cactus with glaucous stems made prominent because of its relatively few spines. The pale straw-colored centrals are fairly long in this form, to 3.5 cm (1.5"). The stems mostly have five ribs as implied by the specific epithet. The ribs are rounded or, when somewhat deflated during drought, have horizontal creases between the areoles. In either state, the thick waxy cuticle is laid down in chevron patterns that point down from the areoles into the sinuses between the ribs thereby accentuating the ascending stems. The species is one of the more widely distributed of the genus, occurring in several of the drier states of northwestern Brazil. Rooted cuts of HBG 57783, a plant from Abbey Garden in the early 1980s. $8.