The ascending leaves of Struthiola eckloniana are opposite and decussate, i.e. each pair is perpendicular to the next one up the stem. They may be clustered densely on the stems or spaced sparsely as in the photo; lower, woody stems become bare with age. The long, narrow leaves are hairless or hairy, particularly upon their margins. The leaves are dark green, about 10 mm long and 3 mm wide.
Leaves (and flowers) resemble those of S. confusa that is smaller, growing in a partly overlapping distribution more to the west with cream or yellow flowers. Confusa comes from the Latin word confundo meaning to confound or confusus meaning confused, disorderly or troubled, probably referring to the plant easily being mistaken for another species (Vlok and Schutte-Vlok, 2010; Moriarty, 1997; Bond and Goldblatt, 1984; iSpot; Andrew, 2012).