Journal Of Los Angeles Nature
*Thanks to [@possiblybuddha for contributing descriptions and photos](https://www.inaturalist.org/observations/169121392#activity_comment_1f8c5bb0-8cc6-4a74-9192-2b8e19ff9b48), and to other iNat users whose photos all link to their iNat observations.* Los Angeles County is home to [19 of the 21 native Oaks](https://www.youtube.com/watch?v=KfJXNRSDJ4o&t=4176s) in California, which makes it one of the most diverse Oak habitats in the world. The native oaks found in and around Altadena (within say a 5 or 10 mile radius) are split into two sections, **Red** (section *Lobatae*), **White** (section *Quercus*) and **Intermediate** (section *Protobalanus*). Oaks within the same section can hybridize with each other, due to being more closely related. Accurate identification of oaks in the field can be very complicated and is not always possible, so don’t get discouraged! Take good photos and upload them to iNaturalist and it’s very likely a local expert will chime in. You may see older observations of some of these labeled as *Quercus dumosa*, but this name is now used only to describe the Nuttall’s Scrub Oak, which does not grow around Altadena. There are also non-native oaks planted as street trees around Altadena/Pasadena such as *Quercus ilex* and *Quercus suber*. Some folks have planted *Quercus lobata* or *Quercus keloggii* here, but their original range isn’t documented as covering the San Gabriel Valley. If you are an intrepid rare plant hunter, you may find a rare specimen of *Quercus johntuckeri*, *Quercus dumosa* or *Quercus lobata* growing in the wild. Be sure to post those to iNat! ### Photographing Oaks A quick note on photographing oaks for iNaturalist. After reading this guide, hopefully it will be clear why it is helpful to have photos of the following for every Oak observation you make: - Photo from far away showing the growth habit (i.e. a picture of the whole plant in context with its surroundings). - Acorn, and/or acorn cap, showing acorn cap detail. You may have to dig around in the leaf litter to find one in the off-season. - Macro or magnified photo of the underside of the leaf surface, with the hairs in focus. - Top of the leaf surface. [Here is an example](https://www.inaturalist.org/observations/188739925) observation with all the above photos. # White Oaks White Oaks are the most often confused, so I will cover them first. White Oaks are in the [Quercus/Quercus section of the genus](https://en.wikipedia.org/wiki/List_of_Quercus_species#Section_Quercus). If you come upon a scrub oak around Altadena that is visibly tomentose (covered in a dense layer of short, matted, woolly hairs or down) abaxially (on the underside of the leaves), it will be QDG (Quercus durata gabrielensis). The other scrub oak option in the region is *Quercus berberidifolia* which is abaxially (underside of leaf) glabrous (smooth) to the naked eye. ### Hybridization White Oaks often hybridize with each other, complicating matters further. *Quercus engelmanii* is not a scrub oak, but rather a larger stature oak similar in size to a *Quercus agrifolia* (Coast live oak). However, the hybrid known was Ewan's Oak (*Quercus x ewanii*), a hybrid between QDG and QE, has been documented as a shorter, scrub like tree and also as a large stature one. ## San Gabriel Oak - QDG (*Quercus durata var. gabrielensis*) Endemic to the southern slopes of the San Gabriels from La Cañada to Pomona. The other durata subspecies (*Q. durata durata*) grows usually on serpentine soils, whereas this one does not have that restriction. Trichomes (hairs) long wavy, readily visible to the naked eye. Form becomes discernible starting at 10x magnification. Tends to grow in drier areas.
![A photo by @possiblybuddha on iNaturalist of a close-up of the underside of a San Gabriel Oak leaf surface.](imgs/6200786a0c3e502c4e072650b84c581cdb01fb93.jpg) [*Photo by @possiblybuddha on iNaturalist*](https://www.inaturalist.org/observations/188739925) ![A photo by @possiblybuddha on iNaturalist of San Gabriel Oak leaf underside and fruit.](imgs/34c0c699866d46057d968839eb879cd34b7a3509.jpg) [*Photo by @possiblybuddha on iNaturalist*](https://www.inaturalist.org/observations/188739925) ![A photo by @possiblybuddha on iNaturalist of San Gabriel Oak top leaf surface.](imgs/f23870244bdfc5ffa66f3cc3161ed617e663daa8.jpg) [*Photo by @possiblybuddha on iNaturalist*](https://www.inaturalist.org/observations/188739925) ![A photo by @possiblybuddha on iNaturalist of a San Gabriel Oak acorn.](imgs/22d616a467279e3a93230f6f52d53857edf1c76b.jpg) [*Photo by @possiblybuddha on iNaturalist*](https://www.inaturalist.org/observations/188739925) ![A photo by @gabimclean on iNaturalist of a San Gabriel Oak in its habit.](imgs/71e553ff1969329ee306176d66a0dc00ec94be9d.jpeg) [*Photo by @gabimclean on iNaturalist*](https://www.inaturalist.org/observations/231767058)
## Scrub Oak - QB (*Quercus berberidifolia*) Not very common in Altadena, but common across the state, and found in nearby areas like the Verdugos. Any scrubby/shrubby oak has a chance of being misidentified as QB because of its generic common name “Scrub Oak” (despite being one of many scrub oaks). Leaf underside (abaxial surface) appears glabrous (smooth) to naked eye. Trichomes visible at 60x magnification - usually far and few between. Tends to grow in mesic (moist) areas.
![A photo by @possiblybuddha on iNaturalist of a Scrub Oak leaf underside, in macro.](imgs/2703575237cf0c81a82c86711fbb610f21614fae.jpg) [*Photo by @possiblybuddha on iNaturalist*](https://www.inaturalist.org/observations/188743670) ![A photo by @possiblybuddha on iNaturalist of a Scrub Oak leaf.](imgs/ce2697d6c9aa204e9d98cc2c7a0d6227c708654a.jpg) [*Photo by @possiblybuddha on iNaturalist*](https://www.inaturalist.org/observations/188743670) ![A photo by @possiblybuddha on iNaturalist of a Scrub Oak leaf underside.](imgs/870cf145c5ebd425c583ad7c8c21f4c0e68b0700.jpg) [*Photo by @possiblybuddha on iNaturalist*](https://www.inaturalist.org/observations/188743670)
## Engelmann Oak - QE (*Quercus engelmanii*) A large stature tree. SoCal endemic. Also known as the Pasadena Oak, although most of the population is in OC/San Diego counties. Trichomes distinctly brown, long rayed, distinctly 3-dimensional form (akin to a crumpled napkin), visible to naked eye when abundant, but are readily deciduous (lack of QE trichomes does not necessarily indicate a specimen is not of QE heritage).
![A photo by @possiblybuddha on iNaturalist of an Engelmann Oak leaf underside in macro, with the hairs in focus.](imgs/a5f6ce8739658b281aba30572c6873f5ab246409.jpg) [*Photo by @possiblybuddha on iNaturalist*](https://www.inaturalist.org/observations/188955130) ![A photo by @possiblybuddha on iNaturalist of an Engelmann Oak tree in its habit.](imgs/118c66bc7538a5878647f3167247e4a29599e617.jpg) [*Photo by @possiblybuddha on iNaturalist*](https://www.inaturalist.org/observations/188955130) ![A photo by @possiblybuddha on iNaturalist of an Engelmann Oak leaf and acorn.](imgs/984be467fa06618b6a644e40bd0ddd3943525fc4.jpg) [*Photo by @possiblybuddha on iNaturalist*](https://www.inaturalist.org/observations/188955130)
## *Quercus x ewanii* (QDG + QE Hybrid) Can have traits of either parent, in varying degrees. E.g. can be a large stature oak with leaf traits from QDG, or a scrub oak with leaf traits from QE (see two examples below).
![A photo by @possiblybuddha on iNaturalist of an Quercus x ewanii in its habit.](imgs/f1a43161182c1988b93d9e890baaef18cd178980.jpg) [*Photo by @possiblybuddha on iNaturalist*](https://www.inaturalist.org/observations/195729905) ![A photo by @possiblybuddha on iNaturalist of an Quercus x ewanii leaf.](imgs/00ba5ba878ef0ddc2be65ecf484ed9e435cce770.jpg) [*Photo by @possiblybuddha on iNaturalist*](https://www.inaturalist.org/observations/195729905) ![A photo by @possiblybuddha on iNaturalist of an Quercus x ewanii leaf underside.](imgs/8728489fa4e05e5655bc6b1c08cf6d25c3aedc21.jpg) [*Photo by @possiblybuddha on iNaturalist*](https://www.inaturalist.org/observations/188742502) ![A photo by @possiblybuddha on iNaturalist of an Quercus x ewanii in its habit.](imgs/34d9349c80170a92daa0e538af899f210546afb2.jpg) [*Photo by @possiblybuddha on iNaturalist*](https://www.inaturalist.org/observations/188742502)
# Intermediate Oaks The Canyon Live Oak is the only oak in the [Quercus/Protobalanus section of the genus](https://en.wikipedia.org/wiki/List_of_Quercus_species#Section_Protobalanus). ## Canyon Live Oak - QC (*Quercus chrysolepis*) This is a large-growth habit oak. It is relatively easy to identify due to size, acorns and location. The leaves are darker green on top, lighter on the bottom, and can be serrated or not. The acorns are very large with a distinctive cap.
![A photo by @adirado on iNaturalist of a Canyon Live Oak leaf top.](imgs/51cc86712969a7796b61766a59ef2e2b17000fcb.jpg) [*Photo by @adirado on iNaturalist*](https://www.inaturalist.org/observations/183450047) ![A photo by @quercusboletus on iNaturalist of a Canyon Live Oak leaf underside.](imgs/3ba8111e3e1d6afffa01486dfd1c0f30eb7a714d.jpg) [*Photo by @quercusboletus on iNaturalist*](https://www.inaturalist.org/observations/203543305) ![A photo by @aachkinazi on iNaturalist of a Canyon Live Oak acorn.](imgs/4f487038e6a8bd9c0650c0584fd729850de9d596.jpg) [*Photo by @aachkinazi on iNaturalist*](https://www.inaturalist.org/observations/190154752) ![A photo by @adrineaa on iNaturalist of a Canyon Live Oak trunk.](imgs/d301c362ecc11b592dc3d3249a12f116b90f94cd.jpg) [*Photo by @adrineaa on iNaturalist*](https://www.inaturalist.org/observations/109234221)
# Red Oaks There are three oaks you may come across in the [Quercus/Lobatae section of the genus](https://en.wikipedia.org/wiki/List_of_Quercus_species#Section_Protobalanus). ## California Live Oak - QAA (*Quercus agrifolia var. agrifolia*) This is the most common Oak in California, and LA County. It is used widely as a street tree. It has a large growth habit, leaves that are serrated, cupped, and are the same shade of green on top and bottom. The acorns are long and skinny with scaled cupolas.
![A photo by @salvmell on iNaturalist of a California Live Oak leaf top.](imgs/3b93423f798e9703316d1361136d376f28bdb4c8.jpeg) [*Photo by @salvmell on iNaturalist*](https://www.inaturalist.org/observations/229620709) ![A photo by @klicklo on iNaturalist of a California Live Oak tree in its habit.](imgs/eff2f84a10eeb122ff98996ebefe81e1abab240b.jpeg) [*Photo by @klicklo on iNaturalist*](https://www.inaturalist.org/observations/231071724) ![A photo by @adirado on iNaturalist of a California Live Oak tree acorn.](imgs/cbf35d53244c712ca031547e45610bbbcbdc6a32.jpg) [*Photo by @adirado on iNaturalist*](https://www.inaturalist.org/observations/128096413)
## Southern Coast Live Oak - QAO (*Quercus agrifolia var. oxyadenia*) Most people think all the *Quercus agrifolia* in the Altadena area are the QAA variety, but this is another more rare type that you may run into. The distinguishing factor is the degree of how tomentose (covered in a dense layer of short, matted, woolly hairs or down) the abaxial (the underside of the leaves) leaf surface is.
![A photo by @possiblybuddha on iNaturalist of a Southern Coast Live Oak leaf underside.](imgs/9f8da8b368b3cc423a7396e050d6cb6d9bdbd1ea.jpg) [*Photo by @possiblybuddha on iNaturalist*](https://www.inaturalist.org/observations/188736070) ![A photo by @possiblybuddha on iNaturalist of a Southern Coast Live Oak leaf top.](imgs/84e31d5ac51f527c6df5a111569c0840eb8fc8ba.jpg) [*Photo by @possiblybuddha on iNaturalist*](https://www.inaturalist.org/observations/188736070) ![A photo by @possiblybuddha on iNaturalist of a Southern Coast Live Oak in its habit.](imgs/db11d9c0bc53afe2e4633b8ac15d86dd71c13813.jpg) [*Photo by @possiblybuddha on iNaturalist*](https://www.inaturalist.org/observations/188736070)
## Interior Live Oak - QW (*Quercus wislizeni*) If you are hiking up in the San Gabriels at elevations above ~3000ft, you may run into oak with a shrub-like growth habit (in our area), and acorns that look similar to QAA.
![A photo by @patrickdyer on iNaturalist of an Interior Live Oak leaf underside.](imgs/8c871a3f31e1fbb1edc52369313bd29ff7410705.jpg) [*Photo by @patrickdyer on iNaturalist*](https://www.inaturalist.org/observations/195130430) ![A photo by @bryanbrasmussen on iNaturalist of an Interior Live Oak acorn.](imgs/15294171ada2b8206740897cb9e572293070e606.jpg) [*Photo by @bryanbrasmussen on iNaturalist*](https://www.inaturalist.org/observations/7157076)
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This work by Max Yasuda is licensed under CC BY-NC 4.0 

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