Although Rubiaceae flowers are generally organized in many-flowered inflorescences, solitary flowers are also found in this genus. The reduction of the number of flowers per inflorescence is often invertedly proportionate to the size of the flowers, which explains the large solitary flowers of some Rothmannia.[1]
Distribution and species
The genus originally had wide distribution, but is now restricted to species found in tropical and southern Africa:[2]
^Robbrecht E, Puff C (1986). "A survey of the Gardenieae and related tribes (Rubiaceae)". Botanische Jahrbücher für Systematik, Pflanzengeschichte und Pflanzengeographie. 108 (1): 63–137.