herbs, rarely annual. Stem sparingly branched, glabrescent to dense-tomentose.
Leaves elliptic to linear, entire, petiolate or sessile, stipules from a short
sheathing base. Inflorescence terminal, rarely pseudo-axillary cymes, di or
tri-chotomous, lax to congested-capitate. Flowers many, small, sessile or
subsessile, white to blue-violet, 4-merous, dimorphic, heterostylous. Calyx
tube very short, often very unequal. Corolla salver-shaped to infundibular,
tube hairy within. Stamens included or exserted. Stigmas bifid, papillate.
Fruits ellipsoid to obovoid, scarcely to distinctly dorsally or laterally
compressed, indehiscent or splitting into 2 mericarps. Seeds 2, oblong to
ellipsoid in stony endocarp.