is one of the larger plant families in the US, with 60 genera and around 650 species, some major families being cryptantha, hackelia, mertensia, oreocarya, phacelia and plagiobothrys. Nearly all are herbs, relatively low growing, and they are often densely covered with hair or bristles, especially on the bracts beneath the flowerheads in the inflorescence. Some have single or small groups of flowers but most produce clusters, spherical or elongated. Individual flowers have five sepals, at the base of a tubular corolla that opens into five petals, with five stamens at the center. Leaves tend to be undivided. Some species, such as those in the cryptantha and oreocarya genera, are very similar in appearance and can be difficult to identify; often inspection of the seeds is required.