Quercus agrifolia (USA)

 

Quercus agrifolia, the coast live oak, is an evergreen oak (highly variable and often shrubby), native to the California Floristic Province. It grows west of the Sierra Nevada from Mendocino County, California, south to northern Baja California in Mexico. It is classified in the red oak section (Quercus sect. Lobatae).

This species is commonly sympatric with canyon live oak, and the two may be hard to distinguish because their spinose leaves are superficially similar.
Coast live oak typically has a much-branched trunk and reaches a mature height of 10–25 meters. Some specimens may attain an age exceeding 250 years, with trunk diameters up to three or four meters, such as those on the Filoli estate in San Mateo County.
The trunk, particularly for older individuals, may be highly contorted, massive and gnarled. The crown is broadly rounded and dense, especially when aged 20 to 70 years; in later life the trunk and branches are more well defined and the leaf density lower.
The leaves are dark green, oval, often convex in shape, 2–7 cm long and 1–4 cm broad; the leaf margin is spiny-toothed (spinose), with sharp thistly fibers that extend from the lateral leaf veins. The outer layers of leaves are designed for maximum solar absorption, containing two to three layers of photosynthetic cells.
These outer leaves are deemed to be small in size to more efficiently re-radiate the heat gained from solar capture. Shaded leaves are generally broader and thinner, having only a single layer of photosynthetic cells. The convex leaf shape may be useful for interior leaves which depend on capturing reflected light scattered in random directions from the outer canopy.
The flowers are produced in early-to-mid spring; the male flowers are pendulous catkins 5–10 cm long, the female flowers inconspicuous, less than 0.5 cm long, with 1-3 clustered together. The fruit is a slender reddish brown acorn 2-3.5 cm long and 1-1.5 cm broad, with the basal quarter enclosed in a cupule; unusually for a red oak, the acorns mature about 7–8 months after pollination (most red oak acorns take 18 months to mature).
 Coast live oak is the only California native oak that actually thrives in the coastal environment, although it is rare on the immediate shore; it enjoys the mild winter and summer climate afforded by ocean proximity, and it is somewhat tolerant of aerosol-borne sea salt. The coastal fog supplies relief from the rainless California summer heat. 
Normally the tree is found on well drained soils of coastal hills and plains, often near year round or perennial streams. 
(From Wikipedia on 10.11.14)
Small tree seen in the Golden Gate Park, San Francisco on 30/9/14.

Acorns, or Oak Nuts seen on the tree.
On searching, could this be Quercus agrifolia?

Yes, …; it does look like Q. agrifolia.

Thanks for confirming.

 
 
  

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