Erect, perennial herb or sub shrub, sometimes ± succulent. Leaves opposite, eglandular, exstipulate, petiolate with glands in the axil. Inflorescence axillary cyme, solitary or paired. Flowers white or pink. Calyx 5-lobed, eglandular within, lobes subulate ± equal, rarely imbricate. Corolla salverform, tube cylindrical, throat constricted, hairy within, lobes overlapping to the left in bud. Stamens 5, inserted below the middle in the inflated part of corolla, included, anthers not connivent with stigma, ovate, lanceolate without enlarged connective. Disc modified into 2 long linear glands -alternating with the carpel. Carpels 2, free, ouvels many, style filiform, stigma capitate, pentagonal. Fruit a follicle, cylindric; seeds numerous, small, rugose, truncate at both ends.