Twigs are critically important in identification of trees, shrubs and vines, especially in wintertime. The buds on the twig are important diagnostic characteristic, as are the leaf traces where the leaves have fallen away. The color, texture, and patterning of the twig bark is also important, as is the thickness and nature of any pith of the twig.
There are two very important different types of twigs: the usual vegetative twigs and fruiting spurs. Fruiting spurs are specialized twigs that generally branch off the sides of branches and leading twigs, and are stubby and slow-growing, with many annular ring markings from seasons past.