Quercus pungens, commonly known as the sandpaper 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...

 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 oak. Sandpaper oak hybridizes with gray oak, Quercus grisea

Quercus grisea

Quercus grisea, commonly known as the gray oak, shin oak or scrub oak, is a deciduous or evergreen shrub or medium sized tree in the white oak group and is endemic to the south central montane regions of North America. It hybridizes with four other oak species where the ranges of each overlap, the...

, in the Guadalupe Mountains of New Mexico and Texas.

Distribution

Sandpaper and Vasey shin oaks are abundant in the Edwards Plateau

Edwards Plateau

The Edwards Plateau is a region of west-central Texas which is bounded by the Balcones Fault to the south and east, the Llano Uplift and the Llano Estacado to the north, and the Pecos River and Chihuahuan Desert to the west. San Angelo, Austin, San Antonio and Del Rio roughly outline the area...

 and the Trans-Pecos

Trans-Pecos

The term Trans-Pecos, as originally defined in 1887 by the Texas geologist Robert T. Hill, refers to the portion of Texas that lies west of the Pecos River. The term is considered synonymous with "Far West Texas", a subdivision of West Texas...

 region of 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...

. They also occur in the Guadalupe Mountains

Guadalupe Mountains

The Guadalupe Mountains are a mountain range located in West Texas and southeastern New Mexico. The range includes the highest summit in Texas, Guadalupe Peak, , and the "signature peak" of West Texas, El Capitan, both located within Guadalupe Mountains National Park, as well as Carlsbad Caverns...

 and westward to the mountains of southeastern Arizona

Arizona

Arizona ; is a state located in the southwestern region of the United States. It is also part of the western United States and the mountain west. The capital and largest city is Phoenix...

 and southwestern 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 Chihuahua and 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...

 states of Mexico.

Description

The sandpaper oak can be a small tree of up to forty feet high or a large shrub that forms thickets. The bark is light brown and papery. The twigs are gray, with short velvety hairs, becoming smooth with age. The buds are dark red-brown, sparsely covered with hairs. The leathery leaves are semi-evergreen, being bright glossy green at first but turning darker with age. It is their rough texture, caused by minute persistent hair bases, that gives the tree its name of sandpaper oak. 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, the female catkins having one to three flowers and the male catkins numerous flowers. The acorn cups are shallow and covered with dense gray hairs. The acorns grow singly or in pairs and are light brown, broadly ovoid with a rounded apex.

Habitat

The preferred habitat of these oaks is on dry limestone or igneous slopes at a height of between 800 and 2000 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...

, usually in communities of oak

Oak

An oak is a tree or shrub in the genus Quercus , of which about 600 species exist. "Oak" may also appear in the names of species in related genera, notably Lithocarpus...

, juniper

Juniper

Junipers are coniferous plants in the genus Juniperus of the cypress family Cupressaceae. Depending on taxonomic viewpoint, there are between 50-67 species of juniper, widely distributed throughout the northern hemisphere, from the Arctic, south to tropical Africa in the Old World, and to the...

 and pinyon pine

Pinyon pine

The pinyon pine group grows in the southwestern United States and in Mexico. The trees yield edible pinyon nuts, which were a staple of the Native Americans, and are still widely eaten...

. In the chaparral formations in the Guadalupe Mountains, it is one of the dominant species and is found growing alongside 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...

and 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:...

. Other plants associated with it include the Mohr shin oak, Quercus mohriana

Quercus mohriana

thumb|left|Typical oak savannaQuercus mohriana, commonly known as the Mohr oak, shin oak or scrub oak, is an evergreen shrub or small tree in the white oak group and is endemic to the south central montane regions of North America...

, 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.