It contains the single species Illecebrum verticillatum, which is a trailing annual plant native to Europe, with whorls of small white flowers borne in the axils of the paired leaves.

Illecebrum verticillatum is native to much of Europe, from the western Iberian Peninsula to Poland;[1] it is rare in Great Britain,[2] and its northernmost station is in Denmark.

[3] Illecebrum verticillatum produces procumbent or decumbent (trailing) stems that may be up to 20 cm (7.9 in) high.

The small flowers are clustered in the axils of the leaves; their petals are much smaller than the white sepals.

The plant is sometimes referred to in published works as whorled knotweed or coral necklace, although it is unclear if these purported common names are actually used in practice.