This Euphorbia lactea is a ghost variety. Normally all our ghost Euphorbia lacteas are crested. But now we have a small number of uncrested (non-crested?) ghostly lacteas. It’s full and proper name is Euphorbia lactea “White Ghost”.
“Lactea” sounds like a milkly name and indeed this is also known as a Milk Bush, in this case a Ghost Milk Bush, although Euphorbia tirucalli, i.e. the Pencil Cactus, is actually more commonly called Milk Bush and E. lactea is more commonly called Candelabra Cactus. Common names can be so confusing! Milk Bushes tend to be more poisonous than other Euphorbias, although not the most poisonous of Euphorbias. African Milk Tree (Euphorbia trigona) is less poisonous, but still nasty. In case you haven’t figured out, the milk part of the name refers to the milky white latex sap which is the poisonous part of the plant.