המועדפים של yerbasanta

This oak was growing on the edge of a serpentine area dominated by Sargent’s Cypress, arcostaphylos and ceanothus species. Although it appeared largely deciduous, it had retained a number of green leaves spread evenly over the tree. There were no sign of any acorns in the vicinity. Presumably a hybrid?

Best fit, but leaves seem consistently too small for this species over many years of observing it!

Maybe a new subspecies?

Similar observations in the Dunes (starting with mine):
https://www.inaturalist.org/observations/69542433
https://www.inaturalist.org/observations/38499081
https://www.inaturalist.org/observations/208623192
https://www.inaturalist.org/observations/104551840
https://www.inaturalist.org/observations/154621069

maybe:
https://www.inaturalist.org/observations/198456983
https://www.inaturalist.org/observations/200307748
https://www.inaturalist.org/observations/113593841

At least 3 clumps seen along this popular corridor for horses.

I'm now convinced they're a vector for noxious invasive species, which means extra monitoring and restoration effort is needed along any popular horse trails.

In an ideal world, there'd be a horse tax specifically for this sort of externality.

Growing right by the western side of the road. A strong candidate for Q. garryana semota x john-tuckeri imo. (EDIT: I suppose most of the "QGS" traits could be Q. lobata as well. Tough to say. The leaf litter, indicating semi-deciduousity, and lobed leaves at the very least indicate some sort of lobed, deciduous parent.)

-QJT is the dominant oak species by far in this region with a minority of Q. agrifolia
-QGS traits: Suckering growth habit/stature, deciduousity, appearance of the leaf litter, lobed leaves and general leaf shape, new leaf shape and growth habit, filamentous bracts, yellow-green color of newer leaves
-QJT traits: spikiness of the lobes, rough/tomentose feeling of the leaves (especially the newer ones), wideness of the leaves, bluish-green color and "dustiness" of the mature leaves, dominant yellow central vein on mature leaves, dominant oak species in the area, material thickness and robustness of the twigs

I don't see any QGS in the vicinity. Since this was by the roadside, it is possible that an acorn got carried down from further up the road by water or human activity, and/or QGS from further north into the mountains pollinated some QJT in the area.

Fagaceae
Juap
Quercus spp.
Scrub oak
This plant was found on San Pasqual Reservation near Chaparral habitat.
This plant was identifiable by the leaf patterns, and there were some acorn tops found still on the tree.

This was a staple food for the Kumeyaay and could also be used for building.

Pinnacles NP

Observed near the intersection of the high peaks trail and the condor gulch trail a couple years ago, before I was aware of iNaturalist.

Initially i had hoped it might be gabilanensis. However, the leaves lack the glaucous surface gabilanensis should have.

Leaves are much more verdant and less pointed than pajaroensis, also lacking the shreddy grey bark

-somewhat clasping leaves, petioles mostly present
-no basal burl
-fruit had fused stones
-leaves are bright green with lobed bases
-new growth was glabrous, leaves were glabrous as well

Same plant as:
https://www.inaturalist.org/observations/148161528

Scraped from upper surface of Quercus agrifolia leaf, with water, colonized by blackish fuzzy growth that looks superficially like green algae or lichen.

At 100 to 400x, digital zoom by cropping on some.

Purple to orange coloration under magnification.

Presumably same organism as:

https://www.inaturalist.org/observations/139011425