Etymology -The name is derived from the Latin Armatus, meaning armed and probably refers to the spiny character of the stems.Armatocereus is a group of tree-like cacti from South America that reaches nearly 40 feet in height. The most distinct feature of these plants is that the stems are segmented as each year's growth cycle creates "pinch points" on the otherwise cylindrical and ribbed stems. Ribs number from 3 to 16. Spines of some species give this genus its Latin namesake "Armed Cereus", but while some species feature many tough spines exceeding 4 inches, some have little or no spines. Flowers are almost all white, but can be red and they have spines on the floral tubes. Fruits, red or green, are also spiny until ripe and the dried flowers remain attached to them. This genus is quite uncommon in cultivation, but from what I can tell this is not because they are any more difficult to grow than other columnars.