Arrojadoa is a genus of cacti, comprising 6 species and several varieties. It is named after the Brazilian Miguel Arrojado Lisboa. The genus occurs only in northern Brazil and is found at rocky places, under shrubs, which support their frail stalk. They are subtropical plants, with very little frost tolerance. The species often have frail stalks that can be upright or procumbent, reaching 2 m high and about 2 to 5 cm thick. There are from 10 to 15 ribs, and ramifications are rare, and usually occur from the base.