Cacti ID

[open'nheart]

I've got a cactus newb question.
I just potted 2 cacti tops a few weeks ago, they were both sold to me as San Pedro, but are obviously different.

from a top down view this one (Trichocereus patchanoi) has 6 spines
6 spine


this one has 5 spines
5 spine
What would this 5 spined be?

 

[Shrabbit420]

San pedro cacti can gain or loose spines at will, I have seen some with only 4, and I have seen some with 8. When I first started growing these cacti I was surprised when the cacti went from having seven spines to six, it just stopped growing that spine. If you watch them very closely you can see it happening as they grow, its very cool.

 

[open'nheart]

interesting, I didn't know this.
very cool. thanks shrabbit