- family balaenicipitidae
- family balaenidae
- family balaenopteridae
- family balanidae
- family balistidae
- family balsaminaceae
- family bangiaceae
- family bathyergidae
- family batidaceae
- family batrachoididae
- family begoniaceae
- family belemnitidae
- family belonidae
- family belostomatidae
- family bennettitaceae
- family berberidaceae
- family betulaceae
- family bible
- family bignoniaceae
- family bittacidae
- family blastodiaceae
- family blattidae
- family blechnaceae
- family blenniidae
- family boidae
- family boletaceae
- family bombacaceae
- family bombycidae
- family bombycillidae
- family bombyliidae
- family boraginaceae
- family bothidae
- family bovidae
- family bradypodidae
- family bramidae
- family branchiobdellidae
- family branchiostegidae
- family branchiostomidae
- family brassicaceae
- family brevicipitidae
- family bromeliaceae
- family brotulidae
- family bruchidae
- family bryaceae
- family buccinidae
- family bucconidae
- family bucerotidae
- family bufonidae
- family burhinidae
- family burmanniaceae
- family burseraceae
- family business
- family buxaceae
- family cactaceae
- family caeciliadae
- family caeciliidae
- family caenolestidae
- family caesalpiniaceae
- family callionymidae
- family calliphoridae
- family callithricidae
- family callitrichaceae
- family calostomataceae
- family calycanthaceae
- family camelidae
- family campanulaceae
- family cancridae
- family canellaceae
- family canidae
- family cannabidaceae
- family cannaceae
- family capitonidae
- family capparidaceae
- family caprifoliaceae
- family caprimulgidae
- family caproidae
- family capromyidae
- family capsidae
- family carabidae
- family carangidae
- family carapidae
- family carcharhinidae
- family carchariidae
- family cardiidae
- family cariamidae
- family caricaceae
- family carpinaceae
- family caryocaraceae
- family caryophyllaceae
- family castoridae
- family casuaridae
- family casuarinaceae
- family cathartidae
- family catostomidae
- family caviidae
- family cebidae
- family cecidomyidae
- family cecropiaceae
- family celastraceae
- family centrarchidae
- family centriscidae
- family centropomidae
- family cephalobidae
- family cephalotaceae
- family cephalotaxaceae
- family cerambycidae
- family ceratodontidae
- family ceratophyllaceae
- family ceratopogonidae
- family ceratopsidae
- family ceratostomataceae
- family cercidiphyllaceae
- family cercopidae
- family cercopithecidae
- family certhiidae
- family cervidae
- family cestidae
- family cetorhinidae
- family chaetodontidae
- family chalcidae
- family chalcididae
- family chamaeleonidae
- family chamaeleontidae
- family characeae
- family characidae
- family characinidae
- family charadriidae
- family chelonidae
- family cheloniidae
- family chelydridae
- family chenopodiaceae
- family chermidae
- family chimaeridae
- family chinchillidae
- family chironomidae
- family chlamydiaceae
- family chlamydomonadaceae
- family chloranthaceae
- family chlorophthalmidae
- family chrysochloridae
- family chrysomelidae
- family chrysopidae
- family chytridiaceae
- family cicadellidae
- family cicadidae
- family cichlidae
- family cicindelidae
- family ciconiidae
- family cimicidae
- family cinclidae
- family circle
- family cistaceae
- family cladoniaceae
- family clathraceae
- family clavariaceae
- family cleridae
- family clethraceae
- family clinidae
- family clupeidae
- family clusiaceae
- family cobitidae
- family coccidae
- family coccinellidae
- family coerebidae
- family colchicaceae
- family colubridae
- family columbidae
- family comatulidae
- family combretaceae
- family commelinaceae
- family compositae
- family congridae
- family connaraceae
- family convallariaceae
- family convolvulaceae
- family coprinaceae
- family coraciidae
- family cordaitaceae
- family cordylidae
- family coregonidae
- family coreidae
- family corixidae
- family cornaceae
- family cortinariaceae
- family corvidae
- family corydalidae
- family corylaceae
- family corynebacteriaceae
- family coryphaenidae
- family cotingidae
- family cottidae
- family court
- family cracidae
- family cracticidae
- family crangonidae
- family crassulaceae
- family cricetidae
- family crocodylidae
- family crotalidae
- family cruciferae