The bush chinquapin or chrysolepis sempervirens is a plant that exists as a small member of the beech family Fagaceae, endemic to the western United States.
Chrysolepis sempervirens falls within the plantae kingdom, the fagales order, the fagaceae family and the chrysolepsis genus. There are two species of Chrysolepis — Chrysolepis chrysophylla and Chrysolepis sempervirens — which like many species in the related genera of Castanopsis and Castanea are called chinquapin, also spelled “chinkapin.”
The first of those, the chrysolepis chrysophylla, does not occur indigenously in San Bernardino County. It is referred to as the golden chinquapin or giant chinquapin and ranges from 66 feet to 131 feet tall as a tree or 10 feet to 33 feet tall as a shrub. It occurs in coastal areas of the Pacific Coast Ranges from Washington near Seattle south to the San Luis Obispo area California Coast Ranges with a disjunct population distribution in the northern Sierra Nevada east of the Sacramento Valley. It rarely grows at elevations above 5,000 feet and has a thick and rough bark.
Chrysolepis sempervirens, the bush chinquapin, does occur in San Bernardino County in both the San Gabriel and San Bernardino Mountains. It also is extant in interior southwest Oregon and California, in the Klamath Mountains, the full Sierra Nevada range, and the San Jacinto Mountains of the Southern California Transverse Range.
Chrysolepis sempervirens exists as a shrub only, ranging from 3.3 feet to 6.6 feet tall. It flourishes mostly at high elevations between 3,300 feet to 9,800 feet in altitude. The leaves are smaller than in the Chrysophylla, at 1.6 inches to 3.1 inches long, with an obtuse (blunt-pointed or rounded) apex. The bark is thin and smooth.
Sometimes referred to as the dwarf golden chinquapin, the chrysolepis sempervirens’ common habitat is rocky slopes, chaparral and conifer forests, and the alpine regions of the coastal ranges and the Sierra Nevada.
It is in leaf all year, and in flower in July. The species is monoecious, meaning its individual flowers are either male or female, but both genders can be found on the same plant. It is pollinated by wind.
It is best suited in light (sandy) and medium (loamy) soils and prefers well-drained but moist soil. The plant can tolerate both acid and neutral soils, growing well in very acid soils, but does require a lime-free soil. It grows well in semi-shade such as light woodland. The plant does well in a sheltered semi-shaded position. The plants can only be grown in oceanic and Mediterranean climates, but upon being introduced to places where it is not indigenous, such as island or coastal areas like Britain, it thrives.
The bush chinquapin is a shrub with simple, entire (untoothed) leaves with a dense layer of golden scales on the underside, which gives it its genus name, from Greek chryso-, yellow, and lepis, scale. It has a thinner layer on the upper side; the leaves persist for 3–4 years before falling.
The fruit is a densely spiny cupule containing usually three sweet, edible nuts, which historically were eaten by indigenous peoples. The fruit also provides food for birds and wildlife. The seeds can be eaten raw or cooked, are very sweet and much appreciated, tasting somewhat like a hazel nut. The small seed is up to 13 millimeters wide.
Chrysolepis is related to the subtropical southeast Asian genus Castanopsis, in which it was formerly included, but differs in the nuts being triangular and fully enclosed in a sectioned cupule, and in having bisexual catkins. Chrysolepis also differs from another allied genus Castanea (chestnuts), in that its nuts take 14 to 16 months to mature, as opposed to 3 to 5 months for the Castanea, as well as having evergreen leaves and the shoots having a terminal bud.
According to the U.S. Forest Service, “Bush chinquapin grows on steep, often south-facing slopes within the coniferous forest zone. It is also found on the more gentle slopes of that zone where disturbance has removed the original forest cover. Low-growing forms of this shrub occur above timberline. Bush chinquapin occurs as high as 12,000 feet but is most common from 1,500 to 6,000 feet in elevation. Bush chinquapin often dominates or codominates the understories of mid-seral coniferous forests adjacent to montane chaparral. Coniferous forests may also contain scattered thickets of bush chinquapin on sites unfavorable to conifer growth, such as rocky outcrops or dry ridges. Bush chinquapin occupies breaks in the overhead canopy where windthrow or tree death has occurred. Bush chinquapin is susceptible to oak wilt, a potentially lethal disease caused by a fungal pathogen (Ceratocyctic fagacearum). Oak wilt is spreading westward from the Great Plains area.”

From: Wikipedia, https://pfaf.org (plants for a future), www.calflora.org and www.fs.fed.us