Quercus ajoensis
An extremely rare oak limited to a few canyons in the Ajo Mountains of southwestern Arizona, with ongoing hybridization with related taxa and threats from drought, wildfires, and buffelgrass invasion.
Common Names
Ajo Mountain Scrub Oak
Summary
Ajo Mountain scrub oak is a small evergreen shrub to 2–3 m tall (rarely a tree) in the Fagaceae, native to southwestern Arizona and Baja California, Mexico, typically growing on igneous slopes at 500–1,500 m elevation. It has gray, scaly or furrowed bark and light brown twigs; leaves are leathery, ovate to oblong with 4–6(-8) spiny teeth per side, blue-green adaxial surfaces and glaucous undersides. Acorns are solitary or paired with a shallow cup, and flowering occurs in spring.
The species is highly restricted in range and considered vulnerable, with some populations protected on public lands; ex situ conservation exists and acorns collected for propagation germinated and were distributed to institutions, while introgression with Quercus turbinella is known in some populations.
Lifecycle
Perennial
Height
6 ft 7 in – 9 ft 10 in
Sunlight Requirements
Ideally partial shade
Soil Type
Igneous slope soils
Bloom Color
Brown or reddish-brown
Bloom Time
Spring
Foliage Color
Blue-green
Fall Foliage Color
No fall color
Leaf Lifecycle
Evergreen broadleaf
Seasons of Interest
Spring
Propagation Methods
Seeds
Taxonomy
- Taxonomic Rank
- Species
- Author
- C.H.Mull.
- Publication
- Madroño 12: 140. 1954
Superior Taxa
- Kingdom
- Plantae
- Subkingdom
- Pteridobiotina
- Phylum
- Angiosperms
- Order
- Fagales
- Family
- Fagaceae
- Genus
- Quercus
- Subgenus
- Quercus subgen. Quercus
- Section
- Quercus sect. Quercus
Synonyms
Quercus turbinella var. ajoensis Quercus turbinella subsp. ajoensis