| Rondeletia volubilis Sessé & Moc., 1888 |
| Rondeletia vulcanicola Standl. & Steyerm., 1940 |
| Rondeletia wendtii Lorence & Cast.-Campos, 1988 |
| Rondeletia yucatanensis Lundell, 1976 |
| Rondeletia zolleriana Standl. & Steyerm., 1940 |
| Rondeletieae Burnett, 1835 |
| Rovaeanthus Borhidi, 2004 |
| Rovaeanthus strigosus (Benth.) Borhidi, 2004 |
| Rovaeanthus suffrutescens (Brandegee) Borhidi, 2004 |
| Rubia L., 1753 |
| Rubia acuminata M. Martens & Galeotti, 1844 |
| Rubia hypocarpia (L.) DC., 1830 |
| Rubia laevigata DC., 1830 |
| Rubiaceae Juss., 1789 |
| Rubieae Baill., 1880 |
| Rubioideae Bremek. ex Verdc., 1958 |
| Rudgea Salisb., 1807 |
| Rudgea alvarezii Borhidi & Lozada-Pérez, 2005 |
| Rudgea ceratopetala Donn. Sm., 1903 |
| Rudgea cornifolia (Kunth) Standl., 1931 |