There are about 50 species in the genus, and among them there is considerable variation. Nevertheless a considerable number of the species fit the same description, of a small (1 cm diameter or less) rather flat 5-petalled blue flower growing profusely on straggly stems, flowering in spring. Colour variation is somewhat frequent within species, and white or pink forms are quite likely to be seen. They are popular in gardens, and cultivated forms often show a mixture of colours. The forget-me-nots need shade, not sun.

Forget-me-nots can be annual or perennial plants. Their root systems are generally diffuse. Their seeds are found in small, tulip shaped pods along the stem to the flower. The pods attach to clothing when brushed against and eventually fall off, leaving the small seed within to germinate elsewhere. Seeds can be collected by putting a piece of paper under the stems and shaking them. The seed pods and some seeds will fall out.

They are widely distributed. Most Myosotis species are endemic to New Zealand, though one or two European species, especially the Wood Forget-me-not, Myosotis sylvatica have been introduced in most of the temperate regions of Europe, Asia and America. Myosotis scorpioides is also known as scorpion grass.

In the United States of America, the forget-me-not is the state flower of Alaska, precisely the Myosotis alpestris.

Forget-me-nots are used as food plants by the larvae of some Lepidoptera species including Setaceous Hebrew Character.