Snow-on-the-mountain and its relatives have unusual flowers. The flowers are the very small structures inside the circles of petal like bracts. The most well known of the relatives is poinsetta, with large showy bracts, but similar small flowers. This is a very large and successful genus. In the old world, it has evolved cactus like species that occupy that niche in arid habitats. The first one that poisoned me was one of those. Candelabra plant is from Sri Lanka. To prove I don't learn well, I rooted that cutting and grew it for many years. The poison in this case comes from the milky sap. The garden culprit was a fragile little annual called petty spurge which you will probably never see here.