| form genus | an artificial taxonomic category established on the basis of morphological resemblance for organisms of obscure true relationships especially fossil forms |
Heliobacter
genus Heliobacter | a genus of helical or curved or straight aerobic bacteria with rounded ends and multiple flagella, found in the gastric mucosa of primates (including humans) |
| bacteria genus | a genus of bacteria |
Aerobacter
genus Aerobacter | aerobic bacteria widely distributed in nature |
Rhizobium
genus Rhizobium | the type genus of Rhizobiaceae, usually occur in the root nodules of legumes, can fix atmospheric oxygen |
Agrobacterium
genus Agrobacterium | small motile bacterial rods that can reduce nitrates and cause galls on plant stems |
| genus Bacillus | type genus of the Bacillaceae, includes many saprophytes important in decay of organic matter and a number of parasites |
| genus Clostridium | anaerobic or micro-aerophilic rod-shaped or spindle-shaped saprophytes, nearly cosmopolitan in soil, animal intestines, and dung |
| genus Nostoc | type genus of the family Nostocaceae: freshwater blue-green algae |
| genus Trichodesmium | a genus of blue-green algae |
Pseudomonas
genus Pseudomonas | type genus of the family Pseudomonodaceae |
Xanthomonas
genus Xanthomonas | a genus of bacteria similar to Pseudomonas but producing a yellow pigment that is not soluble in water |
Nitrobacter
genus Nitrobacter | rod-shaped soil bacteria |
Nitrosomonas
genus Nitrosomonas | ellipsoidal soil bacteria |
| genus Thiobacillus | a genus of bacteria |
| genus Spirillum | a genus of bacteria |
| genus Vibrio | a genus of bacteria |
Bacteroides
genus Bacteroides | type genus of Bacteroidaceae, genus of Gram-negative rodlike anaerobic bacteria producing no endospores and no pigment and living in the gut of man and animals |
Calymmatobacterium
genus Calymmatobacterium | a genus of bacterial rods containing only the one species that causes granuloma inguinale |
Francisella
genus Francisella | a genus of Gram-negative aerobic bacteria that occur as pathogens and parasite in many animals (including humans) |
| genus Corynebacterium | the type genus of the family Corynebacteriaceae which is widely distributed in nature, the best known are parasites and pathogens of humans and domestic animals |
| genus Listeria | a genus of aerobic motile bacteria of the family Corynebacteriaceae containing small Gram-positive rods |
| genus Escherichia | a genus of bacteria |
| genus Klebsiella | a genus of bacteria |
| genus Salmonella | a genus of bacteria |
genus Serratia
Serratia | a genus of motile peritrichous bacteria that contain small Gram-negative rod |
| genus Shigella | a genus of bacteria |
| genus Erwinia | a genus of bacteria |
| genus Rickettsia | can cause typhus and Rocky Mountain spotted fever in humans |
| genus Chlamydia | type genus of the family Chlamydiaceae: diseaseausing parasites |
| genus Mycoplasma | type and sole genus of the family Mycoplasmataceae |
| genus Actinomyces | type genus of the family Actinomycetaceae |
| genus Streptomyces | type genus of the family Streptomycetaceae |
| genus Mycobacterium | nonmotile Gram-positive aerobic bacteria |
Polyangium
genus Polyangium | type genus of the family Polyangiaceae: myxobacteria with rounded fruiting bodies enclosed in a membrane |
Micrococcus
genus Micrococcus | type genus of the family Micrococcaceae |
| genus Staphylococcus | includes many pathogenic species |
| genus Lactobacillus | type genus of the family Lactobacillaceae |
| genus Diplococcus | a genus of bacteria |
| genus Streptococcus | a genus of bacteria |
Spirochaeta
genus Spirochaeta | the type genus of the family Spirochaetaceae, a bacterium that is flexible, undulating, and chiefly aquatic |
| genus Treponema | type genus of Treponemataceae: anaerobic spirochetes with an undulating rigid body, parasitic in warm-blooded animals |
| genus Borrelia | small flexible parasitic spirochetes having three to five wavy spirals |
| genus Leptospira | very slender aerobic spirochetes, free-living or parasitic in mammals |
| protoctist genus | any genus of Protoctista |
| genus Amoeba | protozoan inhabiting moist soils or bottom vegetation in fresh or salt water |
Endamoeba
genus Endamoeba | the type genus of the family Endamoebidae |
| genus Globigerina | type genus of the family Globigerinidae |
| genus Arcella | type genus of the Arcellidae |
| genus Difflugia | genus of protozoans related to ameba |