Euphorbia, also commonly called "Spurge" is one of the largest genera of flowering plants.  Spurge can have some similarities to cactus in regards to shape and the ability to go through droughts although they are not cactus. They have a simplified bloom with no petals. People are drawn to the shape of this Genus as they are indeed known for their architecture. The Euphorbia trigona "Rubra', also called the "Red African Milk Tree", is upright with thorns and leaves mimicking a red fringe coat. 

Images are used for general reference only. The size, shape bloom state and leaf state of each plant will vary.