You never know what kind of common names you’re going to get from a cactus.
(Here’s) a picture of a cactus I have that blooms once every May. Four tall white flowers that look like umbrellas. I would like to know what kind of cactus it is. Thanks.
That’s an Echinopsis alright, formerly known as a Lobivia. As for the particular species, it’s hard to tell from the photo, but it might be Echinopsis subdenudata from Bolivia.