Twigology

The leaves are falling so it’s your last chance to figure out what those trees and shrubs are. Or is it? Do you really need leaves to figure out the identification of woody plants? One of my early blogs was on the topic of using bare twigs to identify woody plants in the winter. Twigs are the most recent growth of a woody plant (a tree or a shrub).

Since twigs are the most recent growth, the characteristics that we look for are often still fresh and noticeable. Here is a review of what I wrote last time (you might be surprised to know that plants haven’t changed since I wrote it in 2010 so it’s all still true!):

• Leaf arrangement: even when the leaves are gone, you can see the leaf scars of where they were.  Are they opposite one another along the stem or arranged in an alternate pattern?  If you can’t see the leaf scars, remember that branches themselves were once leaves - how are the branches arranged?  Focus if possible on the “twigs” – the most recent year’s woody growth.  Be careful to check in multiple places because one twig might have fallen off, or one set might be slightly off, making the arrangement appear to be alternate.  Here is a branch from our native hearts a bustin' (Euonymus americanus), showing off perfectly opposite twig arrangement as well as a pair that aren't perfect:

Euonymus americanus twigs, two examples

• Leaves on the ground can sometimes provide a clue: this is not the most reliable approach, especially if there are a lot of different plants around, but it might give you a few things to start looking at if you recognize the leaves.  For example, you might find maple leaves and several kinds of oak leaves on the ground.  But when you look at the plant in question, you notice it has opposite twig arrangement.  Of those choices, maple is the only one that has oppositely arranged leaves and twigs.

3 oak leaves and maple

• Leaf and bloom buds already formed can be familiar: for some people, memory is all they need to recognize a plant without leaves. Here is a picture of one of my favorite bare twig plants, American beech (Fagus grandifolia):

The twig of American beech (Fagus grandifolia)

• Leaf scars and bundle scars: some plants have very noticeable and unique leaf scars.  Leaf scars are the spots left behind when the leaf fell off. Bundle scars can be found inside the leaf scar – they reflect where vascular bundles connected to the leaf and they can be very unique in number and in the shape of them.  Here is a photo of bitternut hickory (Carya cordiformis) showing its leaf scar and the bundle scars (dots) within the leaf scar.

Bitternut hickory (Carya cordiformis)

• Bark characteristics: some bark is very distinctive and you can learn to recognize some trees by their bark.  You can then verify your identification with another characteristic.  For example, Cornus florida (Flowering dogwood) has rather unique bark and it also has twigs that are opposite one another.  Recognize the bark and then verify it with the twigs.  

• Remaining fruits/seeds left clinging to the twigs: sometimes you can find fruit or seeds clinging to the branches.  Some fruit is in the form of a capsule that may open to release seed, leaving the capsule behind.  Here is a picture of the branch where the fruits of beautyberry (Callicarpa americana) used to be.

These fragile remains held flowers and fruits of beautyberry

I’ve only scratched the surface of a very deep topic. For those of you that would really like the tools to identify winter twigs, I suggest you get a 10x hand lens and a good key. If you’re in the Southeastern US, I recommend “Woody Plants of the Southeastern United States: A Winter Guide” by Ron Lance. In addition to very detailed keys, the book has descriptions of each plant according to winter characteristics and most plants have detailed drawings of the twigs themselves (and a good glossary too!).

So don’t be intimidated by those bare branches – get out there and figure it out. I suggest starting with a tree that you already know and examining the twigs and winter features. Good luck!