- family pyralidae
- family pyralididae
- family pyrolaceae
- family pyrrhocoridae
- family pythiaceae
- family pythonidae
- family rachycentridae
- family rafflesiaceae
- family rajidae
- family rallidae
- family ramphastidae
- family ranidae
- family ranunculaceae
- family rapateaceae
- family raphidae
- family raphidiidae
- family recurvirostridae
- family reduviidae
- family regalecidae
- family relationship
- family resedaceae
- family rhamnaceae
- family rheidae
- family rhincodontidae
- family rhinobatidae
- family rhinocerotidae
- family rhinolophidae
- family rhinotermitidae
- family rhiptoglossa
- family rhizobiaceae
- family rhizophoraceae
- family rhizopogonaceae
- family rhodymeniaceae
- family rhyniaceae
- family rickettsiaceae
- family roccellaceae
- family room
- family roridulaceae
- family rosaceae
- family rubiaceae
- family ruscaceae
- family russulaceae
- family rutaceae
- family rynchopidae
- family saccharomycetaceae
- family sagittariidae
- family salamandridae
- family salicaceae
- family salmonidae
- family salpidae
- family salvadoraceae
- family salviniaceae
- family santalaceae
- family sapindaceae
- family sapotaceae
- family sarcoptidae
- family sarcoscyphaceae
- family sarraceniaceae
- family saturniidae
- family satyridae
- family saururaceae
- family saxifragaceae
- family scarabaeidae
- family scaridae
- family scheuchzeriaceae
- family schistosomatidae
- family schizaeaceae
- family schizophyceae
- family schizosaccharomycetaceae
- family sciadopityaceae
- family sciaenidae
- family sciaridae
- family scincidae
- family sciuridae
- family sclerodermataceae
- family sclerotiniaceae
- family scolopacidae
- family scolytidae
- family scomberesocidae
- family scombresocidae
- family scombridae
- family scorpaenidae
- family scrophulariaceae
- family scutigeridae
- family scyliorhinidae
- family secotiaceae
- family selaginellaceae
- family sepiidae
- family septobasidiaceae
- family serranidae
- family sialidae
- family sillaginidae
- family siluridae
- family simaroubaceae
- family simuliidae
- family sirenidae
- family sisyridae
- family sittidae
- family solanaceae
- family soleidae
- family solenidae
- family soricidae
- family spalacidae
- family sparganiaceae
- family sparidae
- family sphaeriaceae
- family sphaerobolaceae
- family sphaerocarpaceae
- family sphecidae
- family spheniscidae
- family sphingidae
- family sphyraenidae
- family sphyrnidae
- family spirillaceae
- family spirochaetaceae
- family spirulidae
- family squalidae
- family squatinidae
- family squillidae
- family staphylaceae
- family staphylinidae
- family steatornithidae
- family stenopelmatidae
- family stercorariidae
- family sterculiaceae
- family stichaeidae
- family stizidae
- family strelitziaceae
- family streptomycetaceae
- family strigidae
- family stromateidae
- family strombidae
- family strophariaceae
- family struthionidae
- family sturnidae
- family styracaceae
- family suidae
- family sulidae
- family sylviidae
- family symplocaceae
- family synchytriaceae
- family syngnathidae
- family synodontidae
- family tabanidae
- family taccaceae
- family tachinidae
- family tachyglossidae
- family taeniidae
- family talpidae
- family tamaricaceae
- family tapiridae
- family tarsiidae
- family taxaceae
- family tayassuidae
- family tecophilaeacea
- family teiidae
- family tenebrionidae
- family tenrecidae
- family tenthredinidae
- family terebellidae
- family teredinidae
- family termitidae
- family testudinidae
- family tethyidae
- family tetragoniaceae
- family tetranychidae
- family tetraodontidae
- family tetraonidae
- family tettigoniidae
- family theaceae
- family thelephoraceae
- family thelypteridaceae
- family theophrastaceae
- family theraphosidae
- family therapy
- family theridiidae
- family thiobacteriaceae
- family thraupidae
- family threskiornithidae
- family thripidae
- family thymelaeaceae
- family tiliaceae
- family tilletiaceae
- family timaliidae
- family tinamidae
- family tineidae
- family tingidae
- family tipulidae
- family titanosauridae
- family todidae
- family torpedinidae
- family tortricidae
- family toxotidae
- family trachipteridae
- family tragulidae
- family trapaceae
- family tree
- family tremellaceae
- family trephritidae
- family treponemataceae