Most members of the flax family, linaceae, are relatively small herbs, producing small branched clusters of flowers at the top of the stems. Flowers are radially symmetric, with five sepals, five petals and five or ten stamens. Petals tend to be narrow at the base. Leaves are undivided, mostly opposite, less often alternate or whorled. 53 species in three genera (hesperolinon, linum, sclerolinon) are found in the US.