The term "cross vine" refers to a specific type of plant. Let's break it down for you.
Cross vine (noun): It is a woody flowering vine that grows in the southern United States. When you look at the cut (or transverse section) of its stems, they have a shape that looks like a cross.
The cross vine is a unique plant known for its cross-shaped stems and beautiful flowers, mainly found in the southern U.S. You can use it when discussing gardening or the environment.