Its name derives from Greek and literally means "closed cactus", referring to the characteristic of its large and lively tubular flowers, which never open up completely. These are columnar cacti, with few branches present only at the base, characterized by slender and long-limbed stems which are usually erect, but sometimes can also be hanging, depending on the species. They also vary considerably in size, ranging from twenty centimeters, up to two meters in height! What distinguishes them are the dense thin spines that completely cover the stems, which make the plant look covered with some sort of a whitish down. This "down" gives it the typical silvery appearance, sometimes generating thick, intertwined and typically golden tufts. This cactus has a slow growth, but it is also very resistant and able to survive for several decades: a perfect plant to ensure a long-lasting exotic touch to your environments!