Adventures in leaf identification
I have long-term confusion about some small oak trees along our lane. They grow in tangled thickets of underbrush where it's impossible to even guess how many separate trees there are.
Several times, I've tried to look up their leaves in my books. Every time, I think that they look a lot like bear oak. However, bear oak isn't native here, so I always reluctantly decide on blackjack oak.
Here are leaves from two of these trees, growing near each other. The top row of leaves are from the first tree and the bottom row of leaves are from the second tree. Notice the variation just between the two leaves of the second tree (bottom row.)
The two leaves in the bottom row resemble the two types of leaves I find attributed to the blackjack oak in my reference books. The leaf on the left looks like the blackjack oak leaf in my Audubon field guide*. The leaf on the right is similar to the blackjack oak leaf in Trees and Shrubs of Kentucky*. Thus, the tree from which the bottom two leaves came is probably a blackjack oak -- but I'm still not sure about the other tree.
The books I've consulted also mention a yellowish color and some fuzz along the veins on the underside of the leaf, and bristles. None of the leaves in my photo are fuzzy underneath. And, though they are paler on their underside, I wouldn't call them yellowish. Also, I don't see any bristles on them. But perhaps they'll develop fuzz, color, and bristles as the season advances.
Here's a summary of what I've read about blackjack oaks while once again researching their leaf shape. Blackjack oaks are small scrubby trees with crooked, sturdy branches. Their height is usually less than 40 feet, and often much shorter. They grow in thin soil and dry conditions. They don't like shade, so they are usually found at forest edges or on slopes. All of this is a perfect description of the trees I'm calling blackjacks.
Blackjacks are found throughout much of Kentucky, including my county. They are native to every state in the Southeastern U.S. from eastern Kansas to the Atlantic Ocean. It is interesting to note in a map of their distribution that they do not grow in the Mississippi River valley. I suppose the soil is too rich and damp for them.
Like all oaks, blackjacks have great wildlife value. The acorns are eaten by a wide range of animals and birds, and the leaves, twigs, and bark may be nibbled in some seasons as well.
For biographical info on books I've mentioned in this post, please see the bottom of this column.