In the wild, Mexico, they grow to 50' columns, which have a woolly cephalium. Occasionally they branch, but mine have not. Many species, that were in this genus, have been placed in other ones and from what I have heard there is only one remaining. The name Cephalocereus, refers to the cephalium (head) where flowers grow. The light green stems remain columns & have up to 30 low ribs. White twisted coarse hairs virtually cover the body of the cacti.
Cephalocereus senilis has a couple of common names and perhaps more, but these two are the ones I have heard; Old Man Cactus and Old Man of Mexico.
Adromischus ~ Astrophytum ~ Cereus ~ Cyanotis ~ Echinopsis ~ Epiphyllum ~ Espostoa ~ Ferocactus ~ Frithia ~ Gymnocalycium ~ Haworthia ~ Hildewintera ~ Lithops ~ Lophocereus ~ Mammillaria ~ Notocactus ~ Opuntia ~ Pilosocereus ~ Rebutia ~ Schlumbergera ~ Sedum ~ Sempervivum ~ Stenocereus ~ Sulcorebutia ~ Tephrocactus ~ Turbinicarpus ~ Weberbauerocereus