. Dr. DeBerry also recommended
, which includes nice line drawings of herbaceous plants in winter.
In the afternoon we had a hands-on lab to identify 24 species of trees and shrubs. Things like sweetbay magnolia, sycamore, and red maple were easy—I was able to identify about half the specimens on sight. Trickier plants included persimmon, sourwood, and ironwood.
Dr. Perry gives some advice
Examining specimens
Dr. DeBerry reveals the answersFor the plants I didn't know, I had to pull out my new copy of Woody Plants in Winter and work my way through the plant key in the front of the book, and it wasn't always easy to follow. If you don't already know, a plant key is a list of questions about plant characteristics that systematically narrows down the list of possible plants until you arrive at the correct species. At first, it can seem a bit tedious to go through all the questions but with practice you learn where you can skip ahead to save time. Here's an example of the questions you would answer to get to black walnut (with the correct answers in bold).
1. evergreen - go to question 2.
1. deciduous - go to question 31.
31. Leaf and stipule scars lacking, the buds subtended by minute scales - Taxodium
31. Not as above go to 32.
32. Leaf scars opposite or whorled - go to 33.
32. Leaf scars alternate - go to 89.
89. Climbing or scrambling - go to 90.
89. Not climbing - go to 103.
103. Bearing spines or prickles - go to 104.
103. Without spines or prickles - go to 116.
116. Without leaf scars, but with persistent leaf bases - go to 117.
116. With leaf scars - got to 119.
119. Bundle traces distinct, 3 or more in a line - go to 120.
119. Bundle traces one, or many traces scattered or nearly confluent in a line - go to 191.
120. Leaf scars very narrow - go to 121.
120. Leaf scars broader - go to 145.
145. Pith chambered - go to 146.
145. Pith continuous - go to 147.
146. Twigs rather thick; leaf scars large - Juglans, page 61.
146. Twigs slender; leaf scars small - Celtis, page 85.
At this point, the books gives you a choice of two Juglans species: black walnut or butternut. Since it has a notched leaf scar, it must be black walnut. Mission accomplished!

Here are some more pictures of twigs—click on the pictures to find out the species and some of the identifying characteristics.
This workshop was a good experience for me. When I'm identifying plants, I typically look at leaves, fruit, or the overall shape, and I tend to overlook the details of twig structure . But when you do look at these closely, there's a lot of interesting information to learn. Good luck on your id's!