''Quercus cornelius-mulleri'' is a North American species of

oak An oak is a hardwood tree or shrub in the genus ''Quercus'' of the beech family. They have spirally arranged leaves, often with lobed edges, and a nut called an acorn, borne within a cup. The genus is widely distributed in the Northern Hemisp ...

known by the common name Muller oak, or Muller's oak. It was described to science in 1981 when it was segregated from the '' Quercus dumosa'' complex and found to warrant species status of its own. It was named after ecologist Cornelius Herman Muller. It is native to southern

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

and

Baja California Baja California, officially the Free and Sovereign State of Baja California, is a state in Mexico. It is the northwesternmost of the 32 federal entities of Mexico. Before becoming a state in 1952, the area was known as the North Territory of B ...

, where it grows in

chaparral Chaparral ( ) is a shrubland plant plant community, community found primarily in California, southern Oregon, and northern Baja California. It is shaped by a Mediterranean climate (mild wet winters and hot dry summers) and infrequent, high-intens ...

, oak woodlands, and other habitat in foothills and mountains. It can most easily be observed in

Joshua Tree National Park Joshua Tree National Park is a List of national parks of the United States, US National Park located in southeastern California, straddling north-central Riverside County, California, Riverside County and part of southern San Bernardino County, ...

and in the woodlands along the western margins of the

Colorado Desert The Colorado Desert is a part of the larger Sonoran Desert located in California, United States, and Baja California, Mexico. It encompasses approximately , including the heavily irrigated Coachella, Imperial and Mexicali valleys. It is home to ...

San Diego County, California San Diego County (), officially the County of San Diego, is a county (United States), county in the southwest corner of the U.S. state of California, north to its Mexico-United States border, border with Mexico. As of the 2020 United States Cen ...

.Nixon, K. C. (2002)
The Oak Biodiversity of California and Adjacent Regions.
US Forest Service Gen. Tech. Report

Description

''Quercus cornelius-mulleri'' is a bushy

shrub A shrub or bush is a small to medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from trees by their multiple ...

not exceeding 3 meters (10 feet) in height. It is densely branched, its tangled twigs gray, brown, or yellowish, fuzzy when new and becoming scaly with age. The

evergreen In botany, an evergreen is a plant which has Leaf, foliage that remains green and functional throughout the year. This contrasts with deciduous plants, which lose their foliage completely during the winter or dry season. Consisting of many diffe ...

leaves are leathery and thick. They are bicolored: dull gray or yellow-green and faintly hairy on the upper surfaces, and white and quite woolly on the undersides. The wool on the undersides of the leaves is made up of star-shaped leaf hairs that are fused into microscopic plates. The leaf blades are oval with smooth or toothed edges, and measure in length. The fruit is an

acorn The acorn is the nut (fruit), nut of the oaks and their close relatives (genera ''Quercus'', ''Notholithocarpus'' and ''Lithocarpus'', in the family Fagaceae). It usually contains a seedling surrounded by two cotyledons (seedling leaves), en ...

with a cap up to wide covered in light-colored scales and a cylindrical, round-ended nut up to long.

References

External links

*
United States Department of Agriculture Plants Profile: Quercus cornelius-mulleri
*
photo of herbarium specimen at Missouri Botanical Garden, collected in California in San Diego County in 1980
cornelius-mulleri Flora of Baja California Flora of the California desert regions Natural history of the California chaparral and woodlands Natural history of the Mojave Desert Natural history of the Peninsular Ranges Natural history of the Transverse Ranges Flora of California Plants described in 1981 Oaks of Mexico {{Quercus-stub