Pick one category for the following text. The options are - company, educational institution, artist, athlete, office holder, mean of transportation, building, natural place, village, animal, plant, album, film or written work. Armatocereus - Armatocereus (from Latin armatus armed and cereus pliant/soft) is a genus of mostly tree-like cacti from South America (Colombia Ecuador to Peru). These species have a conspicuous constriction at the end of the annual growth. The flowers are mostly white with more or less spiny ovary. The fruits are mostly spiny.
Plant