11. Rank of taxonomic categories Major or obligatory ranks appear in boldface None , genus name species and sub. name italize Subspecies Variety Forma None, genus name plus specific epithet, italize Species None, italize, start with capital letter Genus -inae Subtribe -eae Tribe -oideae Subfamily -aceae (see exceptions) Family -ariae Superfamily -ineae Suborder -ales Order -anae Superorder -idae Subclass -opsida Class -phytina Subphylum -phyta Phylum/Division -bionta Kingdom Standard suffix (ending) Category