- race
- radial
- radiate
- radius
- raffia
- ramatu
- Randomization
- Ranomafana
- RAPD
- rare
- Ratios
- ravenala
- ravintoto
- razana
- Recapitulation
- Recent
- Recognition species concept
- recurrent
- Red Queen Hypothesis
- region
- Regression
- Reification
- relict
- reniform
- reproduction
- Reproductive isolation
- Residual
- respiration
- Restriction enzyme
- Restriction site
- reticulate
- RFLP
- rhinarium
- Ring species
- rivers
- Rooted phylogeny
- Rotation
- royalty
- rudiment
- rugose