Definition: The term "Arceuthobium" refers to a species of tree native to southern Europe. It's characterized by its distinctive, needle-like leaves that are often used in medicinal preparations for various ailments. Definition: Arceuthobium is a genus of deciduous trees native to southern Europe with about 25-40 species. These trees are known for their needle-like leaves, which they use for medicinal purposes due to their high content of saponin.