The larger diameter, longer spines, and blue
versus green color difference are obvious difference with San Pedro in this
side by side comparison.
The Peruvian Torch should always be substantially larger diameter
(thicker) than San Pedro.
Trichocereus Tersheckii is very thick but it is never blue. Tersheckii
is a great one to grow if you have a permanent location and plenty of
space; in 10 years it can look like a giant saguaro cactus--those desert
ones in Arizona.
White spines (they are not called thorns) indicate you do not
have a Peruvian Torch. The spines are always brown.
Longer spines mean more sunlight. Spines can be up to 4 inches, but I
don't think I have seen over 2 or three. That is still a nasty and
dangerous spine. Be careful! Yes, you can end up having surgery to
remove ones deeply imbedded. I once had to pay a plastic surgeon to
remove one just below my knee. I have known growers who had them jammed
up under their fingernails. OUCH!
