Chrysolepis chrysophylla - Golden Chinqapin

This tree was totally new to me. I was out of my truck collecting some knobcone pine cones on Empire Grade that came down in a storm and I see this dark leaved tree with chestnut fruit. I look up for a chestnut tree but there wasn't one. And the fruit were attached. Okay, not hard to figure out what it is once I get home. The Golden Chinqapin is a relative of the chestnut (Castanea) but has male and female flowers in the same inflorescence. This is could be the botanical variety, Chrysolepis chrysophylla var Minor. Trees growing on poor soils, reaching 30 feet or less.

Leaves are evergreen, simple, alternate, lanceolate to narrowly elliptical, 2-5" long, folding upward along the main vein, boat keel like, about 1" wide, dark green upper surface and a golden lower surface.

Plants are monoecous, males at the ends of the catkins. Male flowers creamy white at the ends of the branches forming in middle summer, July here.

Male flowers at the ends or in this picture, at the top of the inflorescence and the females near the bottom.  Looks like my deck needs painting…..

 Really, red berries? Nope, galls formed by the Chinquapin Flower Wasp.

Fruit is a nut, enclosed in a spiny husk (cupule = cup-like structure like those surrounding the base of an acorn), very much like that of a chestnut. These are three-angled to round, but caught a nice triangular one,

Spins on the outer husk variously branched and very sharp. One distinction between this and a chestnut is that there are separations between each of the 3 nuts.

Here is the fruit on the left with a chestnut on the right.

Stems yellowish turning red, yellow star shape pith.

Bark smooth when young, developing over time to become deeply furrowed.

Synonyms: Castanopsis chrysophylla

Misidentification:
A chestnut due to the fruit, but the leaves look totally different.

Location:
Santa Cruz
5187 Empire Grade