Quercus mohriana, commonly known as the Mohr oak, shin oak or scrub oak, is an evergreen

Evergreen

In botany, an evergreen plant is a plant that has leaves in all seasons. This contrasts with deciduous plants, which completely lose their foliage during the winter or dry season.There are many different kinds of evergreen plants, both trees and shrubs...

 shrub or small tree in the white oak group and is endemic to the south central montane regions of North America. The species name mohriana honors the pharmacist and botanist Charles Mohr of Alabama.

Distribution

The Mohr oak is abundant in western Texas

Texas

Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...

. It also occurs in southwestern Oklahoma

Oklahoma

Oklahoma is a state located in the South Central region of the United States of America. With an estimated 3,751,351 residents as of the 2010 census and a land area of 68,667 square miles , Oklahoma is the 28th most populous and 20th-largest state...

 and northeastern New Mexico

New Mexico

New Mexico is a state located in the southwest and western regions of the United States. New Mexico is also usually considered one of the Mountain States. With a population density of 16 per square mile, New Mexico is the sixth-most sparsely inhabited U.S...

 and in the Coahuila

Coahuila

Coahuila, formally Coahuila de Zaragoza , officially Estado Libre y Soberano de Coahuila de Zaragoza is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico...

 state of Mexico

Mexico

The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...

.

Description

The Mohr oak can be a small tree up to six metres high or a large thicket-forming shrub. The bark is light brown, rough and deeply furrowed. The twigs are yellowish or whitish, with short velvety hairs, becoming smooth with age. The buds are dark red-brown, sparsely covered with hairs. The leaves are shiny, leathery, dark blue-gray and densely covered with light gray hairs underneath. They have entire margins and are occasionally toothed. The inflorescence

Inflorescence

An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Strictly, it is the part of the shoot of seed plants where flowers are formed and which is accordingly modified...

, which appears in spring, is reddish. There are female catkins with one to three flowers and male catkins with numerous flowers. The acorn cups are deep and the acorns grow singly or in pairs and are light brown, broadly ovoid with a rounded apex.

Habitat

The preferred habitat of this oak is on dry limestone or calcareous slopes at a height of between 600 and 2500 metres above sea level, in chaparral

Chaparral

Chaparral is a shrubland or heathland plant community found primarily in the U.S. state of California and in the northern portion of the Baja California peninsula, Mexico...

 and desert scrub savanna

Savanna

A savanna, or savannah, is a grassland ecosystem characterized by the trees being sufficiently small or widely spaced so that the canopy does not close. The open canopy allows sufficient light to reach the ground to support an unbroken herbaceous layer consisting primarily of C4 grasses.Some...

. It thrives in regions that receive less than twenty five inches of annual rainfall. It grows in association with true mountain-mahogany Cercocarpus montanus

Cercocarpus montanus

Cercocarpus montanus is a species of shrub or small tree in the family Rosaceae. It is known by various common names, such as mountain mahogany, true mountain-mahogany, alder-leaf mountain-mahogany, and alder-leaf cercocarpus...

, desert ceanothus Ceanothus greggii

Ceanothus greggii

Ceanothus greggii, with the common name Desert Ceanothus, is a species of shrub in the buckthorn family, Rhamnaceae.-Distribution:...

, the sandpaper oak Quercus pungens

Quercus pungens

thumb|left|Typical oak savannaQuercus pungens, commonly known as the sandpaper oak or scrub oak, is an evergreen or sub-evergreen shrub or small tree in the white oak group and is endemic to south central North America. There is one recognised variety, Quercus pungens var. vaseyana, the Vasey shin...

, oneseed juniper Juniperus monosperma

Juniperus monosperma

Juniperus monosperma is a species of juniper native to western North America, in the United States in Arizona, New Mexico, southern Colorado, western Oklahoma , and western Texas, and in Mexico in the extreme north of Chihuahua...

, cane cholla Opuntia imbricata

Opuntia imbricata

The cane cholla is a cactus found in the Southwestern United States and northern Mexico, including some cooler regions in comparison to many other cacti...

, purplefruited pricklypear Opuntia phaeacantha

Opuntia phaeacantha

Opuntia phaeacantha is a species of prickly pear cactus known by the common names tulip prickly pear and desert prickly pear.It is found across the southwestern United States and northern Mexico.-Description:...

, Mexican buckeye Ungnadia speciosa, Texas persimmon Diospyros texana

Diospyros texana

Diospyros texana is a species of persimmon that is native to central and west Texas and southwest Oklahoma in the United States, and eastern Chihuahua, Coahuila, Nuevo León, and Tamaulipas in northeastern Mexico. Common names include Texas Persimmon, Mexican Persimmon and the more ambiguous "black...

, hairy tridens Erioneuron pilosum and plateau oak Quercus fusiformis.