Dodatak:Popis kromista, O
Ob
- Oblongichytriidae
- Oblongichytrium
Oc
Koljeno Ochrophyta Cavalier-Smith, 1995
Chromista → Harosa → Heterokonta
- Octodendron
- Octopyle
Ol
Olpidiomorpha Scherff., 1926
- Olpidiomorpha pseudosporae Scherff., 1926
Chromista → Oomycota → Rozellopsidales
Olpidiopsidaceae Sparrow ex Cejp, 1959
- Bicilium H.E. Petersen, 1910
- Olpidiopsis Cornu, 1872
- Peronium Cohn, 1854
- Pleocystidium C. Fisch, 1884
Chromista → Oomycota → Peronosporea → Olpidiopsidales
Olpidiopsidales M.W. Dick, 2001
- Gracea M. W. Dick, 1997
- Olpidiopsidaceae Sparrow ex Cejp, 1959
Chromista → Oomycota → Peronosporea
Olpidiopsis Cornu, 1872
- Olpidiopsis feldmanni (Aleem, 1952)
- Olpidiopsis magnusii (J. & G. Feldmann, 1955)
Chromista → Oomycota → Peronosporea → Olpidiopsidales → Olpidiopsidaceae
On
Onslowia Searles, 1980
- Onslowia bahamensis E.C.Henry, 1987
- Onslowia endophytica Searles, 1980
Chromista → Ochrophyta → Phaeophyceae → Onslowiales → Onslowiaceae
Porodica Onslowiaceae S.G.A. Draisma & W.F. Prud'homme van Reine
- Onslowia Searles, 1980
- Verosphacela E.C.Henry, 1987
Chromista → Ochrophyta → Phaeophyceae → Onslowiales
Red Onslowiales
- Onslowiaceae S.G.A. Draisma & W.F. Prud'homme van Reine
Chromista → Ochrophyta → Phaeophyceae
Oo
- Oomycota
Op
Podrod Ophidiella
Chromista → Myzozoa → Aconoidasida → Haemosporida → Plasmodiidae → Plasmodium
Or
Orcadia Boltovskoy & Watanabe, 1982
- Orcadia riedeli (Rögl & Bolli, 1973)
Chromista → Foraminifera → Globothalamea → Rotaliida → Globigerinoidea → Hastigerinidae
Ornatanomalina Haque, 1956 †
Chromista → Foraminifera → Globothalamea → Rotaliida → Rotalioidea → Rotaliidae → Cuvillierininae
Os
Osangularia Brotzen, 1940
- Osangularia bengalensis (Schwager, 1866)
- Osangularia brunswickensis Todd & Kniker, 1952 †
- Osangularia cordieriana †
- Osangularia culter (Parker & Jones, 1865)
- Osangularia lens Brotzen, 1940 †
- Osangularia malloryi Serova, 1966 †
- Osangularia navarroana (Cushman, 1938) †
- Osangularia plummerae Brotzen, 1940 †
- Osangularia undulata McCulloch, 1977
Chromista → Foraminifera → Globothalamea → Rotaliida → Chilostomelloidea → Alabaminidae
Ot
- Otosphaera
Ou
†Ouaka Cheng 1986
Chromista → Radiozoa → Latentifistularia → Latentifistulidae
Ov
- Ovatisporangium
- Ovipoculum