Corolla limb subequally 5-lobed; lobes entire; tube enlarged above, sometimes incurved.
Flowers small, solitary-axillary or terminally racemose, bi-bracteolate.
Calyx campanulate, 5-lobed; lobes ovate to lanceolate, acute or obtuse.
Leaves opposite to alternate, linear, entire or trifid.
Annual, rigid, erect, branched herbs.
Capsule globose to subglobose.
Seeds numerous, obovoid.
Ovary 2–4-locular.
Ovules numerous.