Four extant species within one extant genus are widely recognised. Fire ants are several species of ants in the genus Solenopsis. The number of species in the genus depends on taxonomic interpretation. It is the type species of its genus. FishBase recognizes four species in the genus. The largest flowering plant genus, "Astragalus", contains over 3,000 species. It is one of two species in its genus. It is the sole species in the monotypic genus, Ricinus, and subtribe, Ricininae. Mating is less dependent on pheromones than other species in its genus. Some of the species in this genus are quite large. There are 600 described species of this single genus. There is evidence of hybridisation between modern humans and other species of the genus "Homo". The number of species in the genus is controversial. There are 13 species recognized in the genus. This species is much darker than others of the same genus.