Identifying San Pedro Visually

[xctico]

How do you visually identify a San Pedro? WHat are the fisical
caracteristics that tell it appart from other cacti. There's a giant
cacti around my place that I think looks like a san pedro [from what
I've seen in pictures], but perhaps I'm not looking at the right stuff.


The cacti is at least 20feet tall, It starts with one big trunk and
from about 50 cm height it branches into about 12 HUGE branches [each
one of those branches could be a huge catus by itself!], On the big
branches there are no spines, but only the shape of where the spine
should grow, however, there are a couple of small young branches being
born and those do have spines. [small, kind of orange colored, in
groups of three or four - I think, forgot the number].

Ill try to get some pictures.