Young Coast Live Oak with acorns. It should be a good winter for the Acorn Woodpeckers and other animals that depend on acorns. There seem to be many acorns forming on the CLO’s this year.
Flora of North America: Acorn diagram: http://floranorthamerica.org/File:FNA03_P83_Quercus_pg_453.jpeg
My favorite Coast Live Oak (Quercus agrifolia) observations:
Fruiting (acorns): https://www.inaturalist.org/observations/242561028
Mites--source of "hairy armpits" and Galls: https://www.inaturalist.org/observations/219047085
Majestic Oak (with "hairy armpits" and acorns): https://www.inaturalist.org/observations/91810838
Flowering (catkins) and "hairy armpits": https://www.inaturalist.org/observations/141648110
Coast Live Oak (Quercus agrifolia) A.k.a. CLO, is a native, long-lived tree (up to 125 - 250 years) in the High-latitude Oaks (Subgenus Quercus) and Beech (Fagaceae) family. Quercus agrifolia is by far the most common Oak tree on the Monterey Peninsula, CA. Leaves are evergreen, oval, cupped or spoon-shaped (adaxially convex). “Hairy armpits” at leaf veins on underside of CLO leaf distinguishes it from other Quercus species. Margins of mature leaves have sharp spines that are very noticeable when you sit in the leaf litter. Acorns (fruits) are long and slender.
Per Jepson eFlora: Coast Live Oak grows "(6)10--25 m, evergreen; top wide; trunk bark furrowed, +- checkered, +- gray. Leaf: 2.5--6(9) cm; petiole 4--15 mm; blade generally widely elliptic to round, generally adaxially convex, +- dull green, abaxially glabrous to densely tomentose, dull, pale green, tip rounded to spine-toothed, margin rolled under or not, weakly spine-toothed. Fruit: cup 10--16 mm wide, 8--15 mm deep, obconic, scales thin, +- not tubercled, +- glabrous, +- brown; nut 25--35 mm, slender, ovoid, distally acute, shell woolly inside; mature in year 1. "
Jepson eFlora https://ucjeps.berkeley.edu/eflora/eflora_display.php?tid=40530
Many organisms call CLO home. There is a whole INat project called "The wonderful diversity of life on Coast Live Oak" https://www.inaturalist.org/projects/the-wonderful-diversity-of-life-on-coast-live-oak. For example,
What causes those fuzzy, white "hairy armpits" where primary vein meets 2ndary veins? Answer: Mite Apartments. Per INat fredwatson: "the prevailing hypothesis is that they function as dolmatia - places for arthopods to live - in this case, mites. There's an idea that the mites either eat fungi or prey on herbivores that would otherwise damage the leaf. A 2020 paper by Coltharp et al. found support for the dolmatium hypothesis, but didn't find support for the predation or fungivory - perhaps because of small sample size and not necessarily because the process doesn't occur. So, mites live there, and there might be a benefit to the tree."
Flora of North America with botanical illustration: http://floranorthamerica.org/Quercus_agrifolia
Calflora lists 2 subspecies. (includes species distribution map in CA): https://www.calflora.org/app/taxon?crn=6983
Oaks of California, B. Pavlik, P. Muick, S. Johnson, M. Popper, 1991, pp. 25-27
Oak Tree Species I.D. and Ecology: https://oaks.cnr.berkeley.edu/oak-tree-species-id-ecology/
Plants of Monterey County: an Illustrated Field Key, 2nd edition, Matthews and Mitchell, 2015, pp. 180-181.
Monterey County Wildflowers https://montereywildflowers.com/tree-fagaceae-quercus/
Flora of Fort Ord: Monterey County, California, David Styer, 2019, p. 128.
Monterey County Herald article "Slowing Down Oak Moth Caterpillars" Sunday, October 9, 2022, pp. 1,3. Fred Watson and Bruce Delgado were interviewed by Luis Melecio-Zambrano for this front page story.
Fort Ord A Love Story, Dorothy E. Denning, 2024 (1,000+ color photos, trail maps) pp. 138-156 "Majestic Oaks"
5-minute video of Fort Ord Flora and Fauna, produced by David Styer: https://fortordcleanup.com/archives/2020/natural-treasures-of-fort-ord-90-amazing-photographs/
Leaf Terminology: Simple Diagrams/Definitions: https://upload.wikimedia.org/wikipedia/commons/e/e8/Leaf_morphology.svg
Plant Identification Terminology: An Illustrated Glossary, 2nd ed., by James G. Harris and M. Harris, 2022
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Irene's Oaks (Quercus) observations on INaturalist, worldwide: https://www.inaturalist.org/observations?taxon_id=47851&user_id=aparrot1
OAKs (genus Quercus) in general, have a worldwide distribution in Mediterranean climates.
Quercus (Oak) are in the Beech (Fagaceae) family.
Those found in Monterey County are in three groups: Red (or Black) Oaks, Intermediate Oaks, and White Oaks. Red Oaks and Intermediate Oaks have acorns that generally mature over a 2 year period (Coast Live Oak is an exception to this rule). White Oaks have acorns that mature in a single season. Most Red Oaks and Intermediate Oaks are evergreen (California Black Oak being the exception). White Oaks may be either evergreen or deciduous. Hybrid forms are common. All oaks are monoecious, with conspicuous male flowers. Female flowers are found in the axils of the leaves near the tips of the new stems.
Monterey County Wildflowers https://montereywildflowers.com/tree-fagaceae-quercus/
Flora of North America: Acorn diagram: http://floranorthamerica.org/File:FNA03_P83_Quercus_pg_453.jpeg
Photo guide of most California Oaks by group, see https://joycegross.com/galls_ca_oak.php,
and for specifics on which Oaks host which gall wasps see https://www.inaturalist.org/projects/california-plants-with-mystery-galls/journal/44142-california-oak-galls]
UC Oak Tree Species I.D. and Ecology, University of California: https://oaks.cnr.berkeley.edu/oak-tree-species-id-ecology/
Oaks of California by Bruce M. Pavlik, P. Muick, S. Johnson, and M. Popper, 1991
Field Guide to Insects and Diseases of California Oaks by Tedmund J. Swiecki and Elizabeth Bernhardt, USDA, 2006.
Field guide for CA Tree Oaks written, designed, and illustrated by Joshua Zupan and free to download here: https://joshuazupan.com/portfolio/tree-oaks-of-california-a-field-guide
Many organisms call CLO home. There is a whole INat project called "The wonderful diversity of life on Coast Live Oak" https://www.inaturalist.org/projects/the-wonderful-diversity-of-life-on-coast-live-oak.
Trees of the Sierra Nevada Mountains: https://www.csun.edu/science/sierras/trees/frameset.html
Irene's (aparrot1) Profile Page on INaturalist listing Nature Resources (includes online references with links) for Plants, Birds, Fungi, Lepidoptera, Arachnids, Reptiles, Amphibians, Marine Life, Plant Galls, and more: https://www.inaturalist.org/people/3188668
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GALLS (Insect-induced Galls on Oaks References):
Plant Galls of the Western United States: a photographic guide to 536 species of plant galls found west of the Rockies, with 400+ color images and plates, Ronald A. Russo, April 2021. (Available on Amazon)
Gallformers: Identify Galls by name or by host plant https://www.gallformers.org/id
INaturalist Project, Galls of California https://www.inaturalist.org/projects/galls-of-california
California Oak Galls (photo guide), Joyce Gross: https://joycegross.com/galls_ca_oak.php
California Oak Galls Induced by Unknown or Undescribed Species (photo guide), Joyce Gross: https://joycegross.com/galls_ca_oak_undescribed.php