Cephalocereus is the genus that represents about 5 slow growing columnar cactus species from Mexico. The genus used to encompass 48 species but many have been removed. The name means 'Cereus with a cephalium', Cereus being the name of a fairly large category of columnar cactus. In turn Cereus is coming from the latine for 'candle'.
Older specimen develop a cephalium, hairier area on their side, from where the trumpet shaped flowers are coming.
Propagation is by seeds or sometimes by clippings.