Geosiris is a genus in the Iridaceae family of flowering plants, first described as a genus in 1894. It was thought for many years to contain only one species, Geosiris aphylla, endemic to Madagascar. But then in 2010, a second species was described, Geosiris albiflora, from Mayotte Island in the Indian Ocean northwest of Madagascar. Its rhizomes are slender and scaly, and stems are simple or branched. The leaves are alternate, but having no use, are reduced and scale-like. The flowers are light purple.