(Plant Identification for everyone)

   Marin County  |  Plant Groups

Marin Acorns

Acorns are a great way to identify an oak, because they’re pretty easy to tell apart.  Here is a picture list of common acorns found in Marin.  Thanks to Wendy Dreskin (WD) for her acorn samples and clever ways to remember them.

Coast and Interior Live Oak

Quercus agrifolia and Quercus wislizeni


Extensive range in Marin


Beech Family


· Skinny acorn, often with extended point.

· Shingle-style cap

· Interior cap tends to cover a lot of the acorn, compared to Coast.

· Interior Live Oak acorn can grow in the middle of a stem because it lasts 2 years.

Quercus agrifolia 2_Coast Live Oak_Lucas Valley Road_1978-10-08__WF--__WF

Acorn cap looks and feels like rough shingles.

Quercus agrifolia_Coast Live Oak_Lucas Valley Road_1978-10-08__WF--__WF

Long, skiny, pointy acorn. 

Interior Live Oak_Quercus wislizeni__SGM

Acorn growing mid-stem makes this an Interior Live Oak.

Tanbark Oak

Notholithocarpus densiflorus




Beech Family



· Crazy hair cap.

· Hard woody nut shell.

· Roundish acorn.

Tan Oak (Crazy hair)

Cap like crazy hair.  This one
looks like dreadlocks.

Tan Oak (Crazy hair)-4

Roundish acorn.

Tan Oak Acorn Cap_Lithocarpus densiflorus_Pioneer Tree Trail in Samuel Taylor State Park_2009-02-28__KF

Cap can be covered with short spines.

Canyon Live Oak

Quercus chrysolepis


Canyons and slopes


Beech Family



· Top like a beret, coming around the sides of the acorn more than the beanie of the Blue Oak.

· Acorn is less long than the Blue Oak.

Canyon Live Oak (Beret)-4

Cap smooth but slightly bumpy
to the touch.

Canyon Live Oak (Beret)

Cap reaches around sides of the acorn.

Canyon Live Oak_Quercus chrysolepis__SGM

Leaves are tough and thick like other live oaks.

Blue Oak

Quercus douglasii


Valleys and lower slopes


Beech Family

Native – found only in California


· Cap covers just the end of the acorn.

· Cap looks like a beanie.

· Cap smooth but slightly bumpy to the touch.

Blue Oak (Beanie)

Cap looks like a beanie.

Blue Oak (Beanie)-4

Cap sits on top of the acorn.


Leather Oak

Quercus durata


Dry, higher exposed slopes.


Beech Family

Native – found only in California.


· Often two acorns at the end of a stem.

· Top of cap has rough bumps on it.

· Leaves are thick, often fuzzy, and curl under.

Quercus durata_Leather Oak-4

Cap has increasingly rough bumps near the top.

Leather Oak-9

Cap at end of stem.

Quercus durata_Leather Oak--__DLS

Leaves very tough and curled over.

Black Oak

Quercus kelloggii


Lower elevations


Beech Family



· Top is like shingles, and covers more than half of the acorn.

· Run your fingers over the top - the cap is smooth.

· Black Oak leaves are quite red in the spring, and always have points at the end of their lobes.

Black Oak (Shingle top, covers half or more)-4

Cap covers more than half the acorn

Black Oak (Shingle top, covers half or more)-6

Smooth top in layered shingles.

Black Oak-29

Spring leaves red.  Leaf lobes always pointy.

Valley Oak

Quercus lobata


Lower slopes


Beech Family

Native – found only in California


· Top has hills and valleys (Valley Oak, get it?)

· Run your fingers over the top – the cap is bumpy but not rough.

· Cap covers less than half the acorn.

Valley Oak (hills and valleys)

Brown nut has a dull point at the end.

Valley Oak (hills and valleys)-5

Cap has deep valleys and smooth tops.

Valley Oak acorn-5

Here is a green (newly developed) acorn.

© Creative Commons BY NC 3.0.  Contributors (identified by initials) are acknowledged at http://PlantID.Net/Contributors.htm

Reviewed by DLS.  Last Updated 3/24/2014 by BHS. 


Note to botanists – this page uses common vocabulary, sacrificing more precise scientific terms in the interest of general communication.  We hope the loss of precision in wording is, to some extent, made up for by photographs showing key identification points.