Eriosyce islayensis is from Nazca, Peru. Hard to find in the wild since these dark spiny barrels disappear into the gravel beds. Until it has fruit! The bright pink fruit are easy to spot from even a few yards away. But once the fruit are ripe, the seeds are wind blown and then there’s just the cactus left again until next year.
In Peru they are generally watered primarily by the fog. These have to be kept very dry, so that means they are an indoor plant – yes, even in San Francisco.
While very spiny, they are quite variable in the wild. The yellow flowers are a give-away.