All plants in the commelinaceae (spiderwort, or dayflower) family are herbs, with alternate, unlobed, untoothed, clasping leaves, and small clusters of flowers at the top of the stems and sometimes at the upper leaf nodes. There are 8 genera and 57 species in the US, concentrated in the Great Plains and states to the east. This is one of the few plant families that produce flowers with three-fold symmetry; three sepals, three petals and (usually) six stamens, some of which may be infertile. In some species one sepal and one petal may be different in size and shape to the other two, however.