- propriogenic
- proteolysis
- protista
- protobios
- protoperithecium
- protoplasm
- protoplasmatic
- protoplast
- pseudoaposematic
- pseudobivalent
- pseudocardia
- pseudocolumella
- pseudoconidium
- ptyalin
- pubescence
- pubescent
- proteose
- proteus
- protoblast
- protochlorophyll
- protoneurone
- protopathic
- protoplasmic
- pseudepisematic
- pseudoallele
- pseudoalveolar
- pseudoamitosis
- pseudobasidum
- pustulous
- purse
- pustular
- quadruplex
- pustulant
- pustule
- pyrenophore
- race
- rate-factor
- reamimation
- receptivity
- recessive
- recrement
- reduction division
- reffex
- renin
- rennin
- rejuvenesce
- reproductive
- resilifer
- resting
- retardant
- reticulin
- reversion
- revertible
- ring-chromosome
- reticulocyte
- retrorse
- reversionary
- revolute
- rheobase
- reversional
- rhabdoid
- rhabdome
- rheobiotic
- rod
- rostrat
- rostrum
- rosette
- rostra
- rudimental
- sac
- saccate
- round-celled
- rudimentary
- saccule
- sagittate
- rostral
- rostrated
- rudiment
- sagittated
- saprogenous
- sarcode
- saxatile
- scleroid
- sclerous
- saprogenic
- sclereid
- sclerid
- saxicoline
- scabrous
- scalariform
- scrobiculated
- sculp
- secernent
- scrobiculat
- sculpture
- scutellum
- sebaceous
- secrete
- secretion
- section