There are about 600 species of oak in the world and most grow in the northern hemisphere. They can be deciduous, that is, they lose their leaves in winter, or evergreen (they never lose their foliage). Although they are very different from each other in the appearance of the leaves, bark and other characteristic elements, know that all oaks are born from nuts called acorns that contain the seeds. You can recognize the type of oak from the acorns it produces with a few simple clues.
Steps
Part 1 of 2: Characteristics of an Acorn
Step 1. Check the stem on which the acorn grows
Evaluate how long it is and how many acorns are hanging on it.
Step 2. Check the appearance of the dome
The acorn develops with a sort of woody "hat", this can be flaky and have hairy wart-like growths that take the shape of a fringe. The dome could also have a particular color or a design with concentric circles.
Step 3. Check how far the dome covers the walnut
Step 4. Measure the diameter and length of the acorn
Some species of oaks produce elongated ones while others are more squat and spherical.
Step 5. Make a note of the color, if it is pointed downwards or if it has other specific characteristics such as ridges or stripes
Part 2 of 2: Common Oaks in North America
Step 1. Get a list of the varieties that grow in North America and read the descriptions of the various acorns
If you have a walnut to compare to the description or photograph, you can easily identify the species.
- Black oaks produce acorns with a diameter of 2 cm with a pointed end. The dome is flaky with a hairy fringe that covers about half of the walnut.
- The quercus macrocarpa develops the largest acorns, about 4 cm long, with a deep dome that covers at least half of the walnut. It has a flaky dome with fluff.
- Quercus pagoda: has small acorns, about 1 centimeter long. The dome is shallow and covers no more than 1/3 of the walnut.
- Quercus laurifolia: This species also produces small (1 cm) acorns that grow in pairs from each stem. They are light brown in color with reddish-brown domes covering about ¼ of the walnut.
- Quercus virginiana: its acorns are born in clusters of 3-5 elements. They are about 2.5 cm long with a rounded and elongated shape with a pointed end. They have a hat that covers about ¼ of the walnut, the latter is black and shiny; the dome, inside, is light brown.
- Quercus garryuana: has large elongated acorns with small domes.
- Quercus lyrata: this plant is distinguished by its acorns completely enclosed by the dome.
- Quercus stellata: produces brown acorns, about 2 cm long with a dome covering 1/3 - 1/2 of the walnut.
