Pencil Cactus is a stunning succulent that has a very unusual branching pattern and thin green stems that resemble pencils. It doesn't look like a cactus but it is a member of the euphorbia family. It can reach a tall shrub or small tree with warm climate and can turn orange or red under bright sunlight in warm climates. It is popular for use in decorative landscapes, both indoor and outdoor, due to its modern appearance. It does have a milky sap, however, that can cause skin and eye irritation, so care needs to be taken when pruning or propagating the plant.