You may search for the genus name, the genus name authority or for the genera included in a family. The first three letters (e.g. "Rho" or "rho" for Rhodymenia) will often suffice.
In this form you can search for a genus name by entering the whole name (e.g., Gracilaria), the begining of a name (e.g., Gracil%), or the ending (%ocolax).