Nemesia strumosa stem and leaf differences

Notable Nemesia strumosa leaf differences are evident in the photo. Mostly narrow, some lower leaf-pairs are wider, ovate in shape with pointed tips and stem-clasping bases. Tiny oblong leaf-pairs grow from some leaf axils in picture, their sunken midribs pronounced.

Some stems are hairy, possibly glandular-haired, others brownish, low in hairiness and square in cross-section (Manning, 2007; Manning and Goldblatt, 1996; Bond and Goldblatt, 1984; iNaturalist; http://pza.sanbi.org).