Most of the genera are subdivided into species, based on the shape of the clouds or their internal structure. A cloud, observed in the sky and identified as a specific genus, may bear the name of only one species.
(Ci) fibratus
(Ci) uncinus
(Ci) spissatus
(Ac) castellanus
(Ac) floccus
(Ac) stratiformis
(St) nebulosus
(Ac) lenticularis
(St) fractus
(Cu) humilis
(Cu) mediocris
(Cu) congestus
(Ac) volutus
(Cb) calvus
(Cb) capillatus
