GOV.WALES uses cookies which are essential for the site to work. Non-essential cookies are also used to tailor and improve services. By continuing to use this site, you agree to our use of cookies.
Definition: Y ddisgyblaeth academaidd o ddiffinio grwpiau o endidau ar sail nodweddion cyffredin, ac enwi’r grwpiau hynny. Defnyddir yn bennaf yn nghyd-destun dosbarthu organebau byw.