''Quercus tardifolia'', the Chisos Mountains oak or lateleaf oak, is a rare North American species of

oak An oak is a tree or shrub in the genus ''Quercus'' (; Latin "oak tree") of the beech family, Fagaceae. There are approximately 500 extant species of oaks. The common name "oak" also appears in the names of species in related genera, notably ''L ...

. It has been found in the

Chisos Mountains The Chisos Mountains, also known as the Chisos, are a mountain range located in the Big Bend area of the Trans-Pecos region of Texas, United States. The mountain system covers 40 square miles (104 square km) and is contained entirely within the ...

inside

Big Bend National Park Big Bend National Park is an American national park located in West Texas, bordering Mexico. The park has national significance as the largest protected area of Chihuahuan Desert topography and ecology in the United States, and was named after ...

Texas Texas (, ; Spanish language, Spanish: ''Texas'', ''Tejas'') is a state in the South Central United States, South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2 ...

, and in the nearby

Sierra del Carmen The Sierra del Carmen, also called the Sierra Maderas del Carmen, is a northern finger of the Sierra Madre Oriental in the state of Coahuila, Mexico. The Sierra begins at the Rio Grande at Big Bend National Park and extends southeast for about , r ...

across the

Río Grande The Rio Grande ( and ), known in Mexico as the Río Bravo del Norte or simply the Río Bravo, is one of the principal rivers (along with the Colorado River) in the southwestern United States and in northern Mexico. The length of the Rio G ...

in northern

Coahuila Coahuila (), formally Coahuila de Zaragoza (), officially the Free and Sovereign State of Coahuila de Zaragoza ( es, Estado Libre y Soberano de Coahuila de Zaragoza), is one of the 32 states of Mexico. Coahuila borders the Mexican states of N ...

. ''Quercus tardifolia'' is an

evergreen In botany, an evergreen is a plant which has foliage that remains green and functional through more than one growing season. This also pertains to plants that retain their foliage only in warm climates, and contrasts with deciduous plants, which ...

tree with gray bark and reddish-brown twigs. The

leaves A leaf (plural, : leaves) is any of the principal appendages of a vascular plant plant stem, stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", wh ...

are flat, up to long, green on the upper surface and with woolly hairs on the underside, with a few shallow lobes.

Conservation

This species was thought to be extinct, however in May 25, 2022 a remaining specimen was found.SciTechDaily
"Clinging to Life: Scientists Rediscover Oak Tree Thought To Be Extinct."
The Morton Arboretum July 7, 2022

Etymology

The common name Chisos Mountains oak refers to the

range where the species was discovered.

References

External links

Wildscreen Arkive, Chisos Mountains oak ''(Quercus tardifolia)''
— ''photo of herbarium specimen''.
Conabio Naturalista, ''Quercus tardifolia''
— ''photo of live specimen''. tardifolia Endemic flora of Texas Flora of Coahuila Flora of the Rio Grande valleys Big Bend National Park Plants described in 1936 Critically endangered flora of North America Critically endangered biota of Mexico Critically endangered flora of the United States Taxonomy articles created by Polbot {{Quercus-stub