Cephalium is a frequently brightly coloured structure of wool and bristle at the growing tip of certain cacti.
It is most commonly found on cacti of the genus Melocactus and can take a number of colours, forms and shapes.
The cephalium will only begin growing after a cactus has reached a certain size or age.
This plant morphology article is a stub.
You can help Wikipedia by expanding it.This Cactaceae article is a stub.