The genera in the Rubiaceae include: (R to Z)
Ramosmania
Randia
Raritebe
Razafimandimbisonia
Readea
Relbunium
Remijia
Renistipula
Rennellia
Retiniphyllum
Rhachicallis
Rhadinopus
Rhaphidura
Rhipidantha
Rhodopentas
Richardia
Riodocea
Riqueuria
Robbrechtia
Robynsia
Rogiera
Roigella
Ronabea
Rondeletia
Rosenbergiodendron
Rothmannia
Rovaeanthus
Rubia
Rubovietnamia
Rudgea
Rustia
Rutidea
Rytigynia
Sabicea
Sacosperma
Saldinia
Salzmannia
Saprosma
Sarcocephalus
Sarcopygme
Schismatoclada
Schizenterospermum
Schizocolea
Schizomussaenda
Schizostigma
Schmidtottia
Schradera
Schumanniophyton
Schwendenera
Scolosanthus
Scyphiphora
Scyphostachys
Sericanthe
Serissa
Shaferocharis
Sherardia
Sherbournia
Siemensia
Simira
Sinoadina
Sinospiradiclis
Sipanea
Sipaneopsis
Siphonandrium
Sommera
Spathichlamys
Spermacoce
Spermadictyon
Sphinctanthus
Spiradiclis
Squamellaria
Stachyarrhena
Stachyococcus
Staelia
Standleya
Steenisia
Stelechantha
Stenaria
Stenosepala
Stenostomum
Stenotis
Stephanococcus
Stevensia
Steyermarkia
Stichianthus
Stilpnophyllum
Stipularia
Streblosa
Streblosiopsis
Strumpfia
Stylosiphonia
Suberanthus
Synaptantha
Syringantha
T
Tamilnadia
Tammsia
Tamridaea
Tarenna
Tarennoidea
Temnocalyx
Temnopteryx
Tennantia
Tessiera
Theligonum
Thogsennia
Timonius
Tinadendron
Tobagoa
Tocoyena
Tortuella
Trailliaedoxa
Tresanthera
Triainolepis
Tricalysia
Trichostachys
Triflorensia
Trigonopyren
Uncaria
Urophyllum
Valantia
Vangueria
Vangueriella
Vangueriopsis
Vidalasia
Villaria
Virectaria
Warscewiczia
Warszewiczia
Wendlandia
Wittmackanthus
Xanthophytum
Xantonnea
Xantonneopsis
Zuccarinia