Discover 10 Types of Acorns and How to Identify Each 

acorn
Kasabutskaya Nataliya/Shutterstock.com

Written by Arlene Mckanic

Updated: November 14, 2023

Share on:

Advertisement


There are about 500 species of oak trees and every one produces an acorn, which is simply a nut. This nut contains one or two seeds in a shell that’s topped with a cap, or cupule. Even some relatives of the oaks, such as the beeches, also produce acorns.

Overview of Discover 10 Types of Acorns and How to Identify Each

To be honest, most acorns look somewhat alike, and botanists identify each of the different acorns by the size and texture of the cup and the shape and color of the nut to figure out what trees they come from. Here are 10 acorns.

1. California Live Oak Acorn

California live oak, Coast live oak, Quercus agrifolia, tree with dark green oval leaves with spiny margins, up to 3.5 cm long acorn with quarter base enclosed in scaly cupule.

The acorn of the California live oak matures in only seven or eight months.

The acorn of this tree, also called the Encina, is sessile, which means it’s connected directly onto the branch, without a stalk. It’s long, conical, pointed, reddish-brown, and about 1.5 inches long. Its scaly cup covers the top quarter of the nut. The nut itself might have attractive dark stripes. The California live oak’s acorn is notable because it matures much faster than other types of red oak. This acorn matures in only seven or eight months while others take as long as a year and a half.

2. White Oak Acorn

Oak acorns with oak leaves isolated on white background.

Identify the white oak’s acorn through its glossy shell and oval shape.

The white oak’s acorn is ovoid, a glossy tan color, and about 0.75 of an inch to 1 inch long. The caps are scaly and cover the top one quarter of the nut. Sometimes the acorn is attached directly to the branch, though some acorns grow from a stalk. They take a season to mature and fall in October.

3. Swamp White Oak Acorn

dry yellowed fallen leaves and acorns of the swamp oak (Quércus palústris) on a white background isolate

The acorn of the swamp white oak is edible.

The acorn of the swamp white oak is oval and small, being from 0.5 to 0.75 of an inch long, and ranges from light to deep brown in color. You can often find swamp white oak acorns growing in clusters of two to four, and they fall in October. They are also edible.

4. Turkey Oak Acorn

acorns and leaves of turkey oak or austrian oak

You can identify the acorn of the turkey oak by its hairy cup.

The acorns of this beautiful, 130 foot tall tree have hairy/mossy cups that cover half of the acorn, which is notable for its long style, an extension of the plant’s ovary. The cup is light brown. The acorn is green at first then turns a darker brown as it matures. Its length ranges from 0.75 of an inch to 1 inch long or slightly longer. Turkey oak acorns fall in October.

5. Scarlet Oak Acorn

Quercus; coccinea; Scarlet oak; fruits; oak;

The acorns of the scarlet oak are edible but have a bitter taste.

Native to the Northeastern United States, the acorn of this tree is round and has a heavy, scaly cap that encloses about half of the nut. Scarlet oak acorns range from 0.5 an inch to 1 inch long. Though edible, these acorns are notably bitter.

6. Burr Oak Acorn

Burr Oak Acorn, Close Up

The burr oak produces one of the largest acorns.

You can identify the acorns of this oak tree by their cups, which have a hairy look to them and contain most of the nut. Burr oak acorns vary in size but can grow as long as 2 inches, especially in the southern part of the tree’s range. This makes the bur oak’s acorn the largest acorn. It can start dropping as early as late summer or as late as the late fall. The tree starts producing acorns when it’s about 35 and continues to bear until it’s 400 years old. This means the burr oak’s reproductive life is longer than any other oak tree found in North America.

7. Chestnut Oak Acorn

Close up view on a water drop falling from the tip of acorn on a tree branch in autumn in the mystical forests near Kalambaka, Meteora, Thessaly, Greece, Europe. Selected focus on a chestnut oak tree

You can identify the chestnut oak acorn by its rough gray cap.

The thin, rough textured gray caps of this oak tree that’s found in the Eastern United States covers about half of the nut. The acorns mature to reddish brown, can grow from 1 to 1.5 inches in length and fall in October. They usually come in pairs.

8. Holm Oak Acorn

Close up acorn couple on holm oak branch green and colorful bokeh background

The holm oak can produce a large crop of acorns.

The majestic holm oak is found in Mediterranean countries and is an evergreen. Its acorn is about 0.75 of an inch long with a fairly deep cup whose scales are downy and pressed close together. The tree is famous for producing heavy yields of acorns, especially after a season with good rainfall.

9. Chinquapin Oak Acorn

Fruits of an American chinquapin tree (Castanea pumila).

The acorns of the chinquapin oak,

Quercus muehlenbergii

are prized for their sweetness.

As the burr oak has the largest acorns, the chinquapin oak is believed to have some of the smallest. They’re oval, dark brown or black, have a distinctive silvery cup and grow from a stalk. Unlike a lot of acorns, which are bitter from the amount of tannins in their flesh, the chinquapin acorn is known for its sweetness.

10. Pin Oak Acorn

Close up of a pair of two pin oak acorns on a branch in the shade in a sunny meadow field with leaves

Pin oak acorns grow alone or in small groups.

You can identify the acorns of this oak tree that’s often planted in cities and suburbs by their round shape and flat tops. They’re about half an inch long, nearly black in color when they’re ripe and topped by a scaly and thin cupule. This cupule covers about one third of the nut. You’ll often see pin oak acorns growing alone or in groups of two or three.

Summary of Discover 10 Types of Acorns and How to Identify Each 

AcornDescription
1California Live Oak Acornlong, conical, and reddish-brown
2White Oak Acorntan, glossy, and oval-shaped
3Swamp White Oak Acornoval, small, and brown variations
4Turkey Oak Acornbrown with mossy cap
5Scarlet Oak Acornscaly cap and bitter taste
6Burr Oak Acornlarge with hairy cup
7Chestnut Oak Acornreddish-brown with rough, gray cap
8Holm Oak Acorn.75 inches long
9Chinquapin Oak Acornoval, small, with silvery cup
10Pin Oak Acornnearly black with flat top


Share this post on:
About the Author

Arlene Mckanic

Arlene Mckanic is a writer for A-Z Animals whose focus is on plants and animals of all kinds, from ants to elephants. She has a Bachelor's Degree from City College of New York. A resident of South Carolina, she loves gardening and though she doesn't have pets, a black racer snake does live in her kitchen.

Thank you for reading! Have some feedback for us?