Quercus oblongifolia

Species of oak tree

Mexican blue oak

Conservation status

Least Concern (IUCN 3.1)[1]

Scientific classification
Kingdom:  | Plantae
Clade:  | Tracheophytes
Clade:  | Angiosperms
Clade:  | Eudicots
Clade:  | Rosids
Order:  | Fagales
Family:  | Fagaceae
Genus:  | Quercus
Subgenus:  | Quercus subg. Quercus
Section:  | Quercus sect. Quercus
Species:  |

Q. oblongifolia

Binomial name
Quercus oblongifolia

Torr.

Natural range of Quercus oblongifolia

Quercus oblongifolia, commonly known as the Mexican blue oak, Arizona blue oak, Blue live oak or Sonoran blue oak, is an evergreen small tree or large shrub in the white oak group.[2][3]

## Distribution

[edit]

Quercus oblongifolia grows in high grasslands, canyons and mesas in southwestern United States (Texas, Arizona and New Mexico) and northwestern Mexico (Baja California Sur, Chihuahua, Coahuila, Sinaloa and Sonora states).[4][5][3] Mexican blue oak is closely related to Engelmann oak "Quercus engelmannii" in Southern California. The two species may be conspecific.[4]

## Description

[edit]

The Mexican blue oak is a small evergreen tree growing 5–8 metres (16–27 feet) tall with a rounded crown. At higher elevations it is typically a large shrub. The trunk is up to 50 centimetres (20 inches) in diameter and the bark is light gray and densely furrowed. The twigs are yellowish brown and hairless with reddish brown buds. The leaves are small, alternate and oblong, with entire margins, leathery, bluish-green above and mid green below. The flowers appear in spring at the same time as the old leaves are being shed and new leaf growth starts. The male flowers form yellowish-green catkins and the female flowers are solitary or paired and grow in the leaf axils. The light brown acorns are ovoid or oblong, about 2 cm (3⁄4 in) long and lodged in scaly, bowl-shaped cups about one third the length of the nut.[4][6]

## Habitat

[edit]

The Mexican blue oak is common at elevations of 1,200 to 1,800 m (4,000–6,000 ft). It is often found on thin sandy soils in semi-arid regions and is the dominant species in lower open oak woodland where it grows in association with Arizona white oak (Quercus arizonica) and Emory oak (Quercus emoryi).[7] It is an important constituent of pinyon–juniper communities.[8] where it grows in association with species of pine and juniper, Arizona rosewood (Vauquelinia californica), shrubby buckwheat (Eriogonum wrightii), catclaw mimosa (Mimosa aculeaticarpa), bullgrass (Muhlenbergia emersleyi), plains lovegrass (Eragrostis intermedia), fendlerbush (Fendlera rupicola) and wolftail (Lycurus phleoides).[7]

## Cultivation

[edit]

Mexican blue oak "Quercus oblongifolia" popularity in landscaping has been increasing in California with many plantings at Apple Park and other Bay area plantings. The fast growth and beautiful blue foliage makes selections from trees in Arizona the best for cultivation. [9][10]

## References

[edit]

1. ^ Beckman, E. (2016). "Quercus oblongifolia". IUCN Red List of Threatened Species. 2016: e.T78969903A78969911. doi:10.2305/IUCN.UK.2016-1.RLTS.T78969903A78969911.en. Retrieved 12 November 2021.
2. ^ "Lady Bird Johnson Wildflower Center - The University of Texas at Austin". www.wildflower.org. Retrieved 19 May 2022.
3. ^ a b "SEINet Portal Network - Quercus oblongifolia". swbiodiversity.org. Retrieved 19 May 2022.
4. ^ a b c Nixon, Kevin C. (1997). "Quercus oblongifolia". In Flora of North America Editorial Committee (ed.). Flora of North America North of Mexico (FNA). Vol. 3\. New York and Oxford: Oxford University Press - via eFloras.org, Missouri Botanical Garden, St. Louis, MO & Harvard University Herbaria, Cambridge, MA.
5. ^ Kartesz, John T. (2014). "Quercus oblongifolia". County-level distribution map from the North American Plant Atlas (NAPA). Biota of North America Program (BONAP).
6. ^ Virginia Tech: Mexican blue oak Archived May 9, 2011, at the Wayback Machine
7. ^ a b Pavek, Diane S. (1993). "Quercus oblongifolia". Fire Effects Information System (FEIS). US Department of Agriculture (USDA), Forest Service (USFS), Rocky Mountain Research Station, Fire Sciences Laboratory.
8. ^ Pieper, Rex D.; Wood, M. Karl; Buchanan, Bruce B. 1988. Pinyon-juniper woodlands of New Mexico: a biological and economic appraisal. Special Report 73. Las Cruces, NM: New Mexico State University, College of Agriculture and Home Economics: 1-11.[5258]
9. ^ "Apple Park - a Spaceship and 9000 Trees". 27 September 2017. Archived from the original on 21 June 2021. Retrieved 25 September 2019.
10. ^ Cottam, Walter P.; Tucker, John M.; Santamour, Frank S. (1982). Oak hybridization at the University of Utah. Publication / State Arboretum of Utah. Salt Lake City: State Arboretum of Utah. ISBN 978-0-942830-00-2.

Taxon identifiers

Quercus oblongifolia|

* Wikidata: Q3414214
* Wikispecies: Quercus oblongifolia
* BioLib: 217702
* CoL: 4R5NG
* EoL: 1151408
* EPPO: QUEOB
* FEIS: queobl
* FNA: 233501068
* GBIF: 2879993
* iNaturalist: 132076
* IPNI: 296515-1
* ITIS: 19390
* IUCN: 78969903
* NatureServe: 2.142790
* NCBI: 1435025
* Open Tree of Life: 3930590
* PfaF: Quercus oblongifolia
* Plant List: kew-174136
* PLANTS: QUOB
* POWO: urn:lsid:ipni.org:names:296514-1
* Tropicos: 13100395
* WFO: wfo-0000292213