January is an especially good month to notice the field marks of a wide range of plants. For one thing - winter-proof features like tree bark, twigs, and branching patterns are important cues. So are berries, empty seed cases and the dried flower heads of winter-killed plants.

But larger factors too play a role - like the extra minutes of daylight, the added brightness of the usual snow cover, and the snow's ability to showcase the underlying structures of foliage-free plants.