Wings are reduced to a pair of prominent ribs in upper pitchers.

Leaves are quite large, biternate and petiolated, with a prominent central rib.

The sculpture of the shell shows prominent axial ribs with a polished surface.

Like terrestrial pitchers, they lack wings, instead having a pair of prominent ribs.

It has many soft, flat, somewhat hairy leaves which often have prominent ribs.

The fruit is green, with up to five not very prominent ribs.

Especially was I enamoured of my painfully prominent ribs.

The stem is bluish green with 6-9 prominent ribs.

His skin was as white as paper, stretched tight over prominent ribs.

Instead, they bear two prominent ribs running down the front, 3-5 mm apart.