Fraxinus anomala Torr. ex S. Watson
Viridiplantae > Streptophyta > Streptophytina > Embryophyta > Tracheophyta > Euphyllophyta > Spermatophyta > Magnoliopsida > Mesangiospermae > eudicotyledons > Gunneridae > Pentapetalae > asterids > lamiids > Lamiales > Oleaceae > Oleeae > Fraxinus > Fraxinus anomala [1]
![Fraxinus anomala plant in habitat. Photo by Bryant Olsen [2].](/crfs/images/native-plants/plant-directory/singleafash-first.jpg)
Fraxinus anomala plant in habitat. Photo by Bryant Olsen [2].
Shrub or small tree, commonly 2.5–4 m tall, usually with many stems; branchlets 4-angled, glabrous. Leaves glabrous, the leaflet blade ovate to oval or subreniform, from somewhat longer than broad to broader than long, crenate-serrate to subentire, 1.5–7.5 (-8.5) cm long, 1–6 (-7.5) cm wide, acute to obtuse or subcordate basally, acute to rounded or emarginate apically, sometimes 2–3(5 or 7)-foliolate or transitional to simple. Flowers usually perfect; anthers oblong; calyx campanulate, persistent; petals lacking. Fruit samaras, oblanceolate to elliptic or obovate-oblanceolate, emarginate, winged almost to the base, 12–27 mm long, 5–12 mm wide [3].
![Photo of leaf and samara of Fraxinus anomala. Photo by Stan Shebs [4].](/crfs/images/native-plants/plant-directory/singleleafash-sec.jpg)
Photo of leaf and samara of Fraxinus anomala. Photo by Stan Shebs [4].
Fraxinus anomala is different in many ways from other Ash species in Southern Utah. First, Single-leaf Ash grows in dry communities such as slick rock or open, dry mountain sides. Other Ash species are commonly found in moist or riparian communities. Most Ash species have compound leaves with more than 5 leaflets. Single-leaf Ash gets its common name from its seemingly simple leaf. Occasionally, F. anomala can be found with clearly compound leaves with 3-5 leaflets, but most often the leaves appear to be simple with inconspicuous compounding [3].
The genus Fraxinus was named by Linnaeus in 1753. Fraxinus anomala was first discovered to western science when it was collected by Newberry and Palmer in Utah in 1850 and then named by John Torrey in 1871 [6]. The specific epithet anomala means anomaly in latin. This was used to refer to how different this plant is from its close relatives due to its simple leaves [7].
![Photo of leaf showing few leaflets on Fraxinus anomala. Photo by Stan Shebs [5].](/crfs/images/native-plants/plant-directory/singleleafash-third.jpg)
Photo of leaf showing few leaflets on Fraxinus anomala. Photo by Stan Shebs [5].
The wood of Singleleaf ash has been used as tool handles by early settlers and indigenous tribes [7]. Seeds were used by the Navajo tribes as a sacred item in their prayers for rain, and the Hopi would make prayer sticks with the plant [9]. Now, the modern landscaper might use this tree as a native, drought tolerant option for a tree or a shrub, especially since it has a higher tolerance for poor soil and inconsistent rains compared to other native species of Ash [10].
![County-level distribution map of Fraxinus anomala [11].](/crfs/images/native-plants/plant-directory/singleleafash-fourth.jpg)
County-level distribution map of Fraxinus anomala [11].
When assessed for the threatened species list in 2017, Fraxinus anomala was determined to be of least concern for endangerment of extinction [12].
Singleleaf Ash grows in plant communities such as mountain brush, pinyon-juniper, Colorado Plateau shrub, and ponderosa pine at 900-2625 m [13]. Singleleaf Ash grows well in a variety of soils and can tolerate many different soil types and is often found on mountain slopes with poor soil quality. The seed of Fraxinus anomala is an indehiscent samara (a papery, winged seed that does not open upon maturity). The dormant, mature seeds drop in late summer or fall. Seeds require temperature stratification in anticipation for the changing of the seasons to germinate. The samaras may germinate after their first winter, but the seeds can be viable for many years and withstand a large range in temperature. It has been hypothesized that the viability and dormancy of the seeds of this tree aid in rebuilding populations after wildfires and other destructive events [14].
United States Forest Service Fire Effects Information System (FEIS)
[1] Schoch CL, et al. NCBI Taxonomy: a comprehensive update on curation, resources and tools. Database (Oxford). 2020: baaa062. PubMed: 32761142 PMC: PMC7408187.
[2] Olsen, B. (n.d.) photograph https://www.flickr.com/photos/bryanto/3557635802
[3] Welsh, Stanley L.; Atwood, N. Duane; Goodrich, Sherel; and Higgins, Larry C., "A Utah Flora, Fifth Edition, Revised" (2015). Books by Faculty of the Monte L. Bean Life Science Museum. 4. https://scholarsarchive.byu.edu/mlbm/4
[4] Shebs, S. (n.d.). photograph. https://commons.wikimedia.org/wiki/File:Fraxinus_anomala_
[5] Shebs, S. (n.d.). photograph. https://commons.wikimedia.org/wiki/File:Fraxinus_anomala
[6] Fraxinus anomala variety anomala (Single Leaf Ash) Oleaceae (Olive Family). Southwest Colorado wildflowers. (n.d.). https://www.swcoloradowildflowers.com
[7] Arches National Park. (2022). Singleleaf Ash. National Parks Service. https://www.nps.gov/arch/learn/nature/oleaceae_fraxinus_anomala.htm#:~:text=Other%3A%20The%20genus%20name%2C%20%E2%80%9C,does%20not%20have%20compound%20leaves.
[8] W., J. Barnes, R. Kjelgren, R. Sutton, T. Cerny, and C. Johnson. 2003. Water wise: Native Plants for Intermountain Landscapes. Utah State University Press.
[9] Wyman, Leland C. and Stuart K. Harris, 1951, The Ethnobotany of the Kayenta Navajo, Albuquerque. The University of New Mexico Press, page 35
[10] University, U. S. (n.d.). Utah native plants for the landscape: Single-leaf ash. USU Center For Water-Wise Landscaping. https://extension.usu.edu/cwel/native-single-leaf-ash.
[11] Characteristics Fraxinus anomala Torr. ex S. Watson. USDA plants database. (n.d.). https://plants.usda.gov/home/plantProfile?symbol=FRAN2
[12] Oldfield, S., Samain, M.-S., Westwood, M. & Martínez Salas, E. 2017. Fraxinus anomala. The IUCN Red List of Threatened Species 2017: e.T96443671A96443673. https://dx.doi.org/10.2305/IUCN.UK.2017-3.RLTS.T96443671A96443673.en. Accessed on 28 May 2024.
[13] Van Buren, R., Cooper, J. G., & Shultz, L. M. (2014). Woody Plants of Utah a field guide with identification keys to native and naturalized trees, shrubs, cacti, and vines. Utah State University Press.
[14] Fire effects information system (FEIS). US Forest Service Research and Development. (n.d.). https://www.fs.usda.gov/research/rmrs/products/dataandtools/tools/fire-effects-information-system-feis
