Rugose is the technical term meaning that a surface is wrinkled. Corrugate (or corrugated) is a synonym. Rugulose means finely or slightly wrinkled; as used in this website, it refers to the sort of slight puckering that paper exhibits when it has been wetted and then left to dry
A reticulate surface has ridges (or sometimes just color changes) that mark out rectangles on the surface. Actually, any kind of clear marking out of cells of some shape will do; the markings on the stem in the picture are just regular enough to be considered reticulations. In some cases, the ridges that form the pattern are called a reticulum. Something that's called a reticulum is often not as regular as reticulations
If the stalk has similar ridges running from top to bottom, it is also called striate. Most sources call this longitudinally striate, to indicate that the ridges run along the length of the stem. But that's pretty much the only type of striations a stem has, so in this website I just leave the "longitudinally" out.