Trichocereus species. This may have been lumped back into Echinopsis. I'm guessing Echinopsis smirziana (=Trichocereus smirzianus). If you're a cacti lover and know the nave of this huge flowered, apical blooming columnar cacti (quite a mouthful), please let me know.
In any case,this cacti appears to bloom late at night through early morning, only to close by mid-day. The 4 gorgeous, white, apical flowers lasted a few days (3-ish) and then closed up for good. They are amazing, especially in the early morning sun.
Most times the cactus stores carry the more common Trichocereus pachanoi (San Pedro Cactus) which is rumored to be mildly hallucinogenic. It amazes me that anyone would be willing to risk all those spines but someone obviously did. I found this really cool cactus as Exotic Gardens, a local cactus and succulent shop.
