Rubiaceae are an easily recognizable family characterized by opposite leaves that are simple and entire, with interpetiolar stipules, tubular sympetalous corollas and an inferior ovary. Exceptionally, there are some plants that have only a single leaf at each node, alternating from one side to the other. In these cases, the alternate leaf arrangement is produced through the suppression of one leaf at each node.[7] A wide variety of growth forms are present in the Rubiaceae. While shrubs are most common, members of the family can also be trees, lianas or herbs. The flowers, which are usually bisexual, have a 4–5 lobed calyx and generally a 4–5 lobed corolla, 4 or 5 stamens and two carpels