R

1. Rafflesia - 20

2. Raoulia - 27

3. Rapatea - 22

4. Raphia - 21

5. Ravenea - 20

6. Rebutia - 24

7. Renanthera - 20

8. Retiniphyllum - 20

9. Rhamphidium - 22

10. Rhaponticum - 26

11. Rhizohypnum - 24

12. Rhodomyrtus - 25

13. Rhodophiala - 27

14. Rhomboda - 21

15. Rhynchanthera - 20

16. Rhynchostele - 23

17. Ricinocarpos - 28

18. Ritchiea - 21

19. Roella - 21

20. Roscoea - 23

21. Ruilopezia - 24

22. Rungia - 23

23. Rutidea - 22