Forest saguaros have thin and flexible creeping stalks and air roots on them, which deliver additional moisture from the air. As a rule, saguaros grow close to the edges of the forest, where there is more light and the air circulates freely between the trees. In case of drought their stalks wrinkle, but with the first rain they become juicy and green again. That’s why these types of cactus belong to another group of cacti – to xerophytes. This group is much bigger than the group of epiphytes, and includes various species from different areas of habitation.
Hylocereinae already have the means of protection from the excessive water evaporation or overheat of the stalk. For example, grey wax bloom and short but strong thorns of celenicereus, a countless number of small setaceous barbs of aporocactus and chamaecereus, etc.