[3] The Swedish taxonomist Carl Linnaeus of the 18th century named the genus after the two Dutch botanists Jan Commelijn and his nephew Caspar, each representing one of the showy petals of Commelina communis.

[2] Several species, such as Commelina benghalensis, are eaten as a leaf vegetable in Southeast Asia and Africa.

[5] Plants in the genus are perennial or annual herbs with roots that are usually fibrous or rarely tuberous or rhizomatous.

The inflorescence is composed of one or two cincinni, also called scorpioid cymes, which are monochasia (i.e. cymes with a single branched main false axis) in which the lateral branches arise alternately on opposite sides of the false axis.

The cincinni are enclosed in a folded spathe, a modified leaf, which is often filled with a mucilaginous liquid.

The spathe may either have completely distinct margins or they may be fused to varying degrees at the basal end.

Flower colour is most typically blue, but lilac, lavender, yellow, peach, apricot and white also occur.