Erect, annual-biennial herb. Basal leaves rosulate, cauline leaves opposite, linear-lanceolate or ovate. Inflorescence a pedunculate cyme or flowers solitary. Flowers bisexual, zygomorphic, pentamerous, campanulate (rarely tubular). Calyx mostly divided to base or forming a very small tube, not provided by an inner membrane. Corolla campanulate, blue, purple, violet or pink, rarely white, plicae or subsidiary lobes of corolla absent, fimbriae absent or throat naked. Stamens corresponding the number of petals. Anthers strictly basifixed, sagittate, dark coloured, filaments inserted near sinuses of corolla lobes and provided with papillae or hairs at base. Nectaries usually present in pairs at the base of and alternating with petals.
Ovary superior, unilocular, with parietal placentation and fewer ovules, stigmas 2, with elongated projections, subsessile-sessile. Capsule ovoid or cylindric, stipitate, few seeded, dehiscing septicidally into two halves. Seeds light brown, slightly bigger in size, globose-ovoid, slightly reticulate.