''Olneya tesota'' is a

perennial In horticulture, the term perennial ('' per-'' + '' -ennial'', "through the year") is used to differentiate a plant from shorter-lived annuals and biennials. It has thus been defined as a plant that lives more than 2 years. The term is also ...

flowering

tree In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, e.g., including only woody plants with secondary growth, only ...

of the family

Fabaceae Fabaceae () or Leguminosae,International Code of Nomen ...

, legumes (peas, beans, etc.), which is commonly known as

ironwood Ironwood is a common name for many woods that have a reputation for hardness, or specifically a wood density that is denser than water (approximately 1000 kg/m3, or 62 pounds per cubic foot), although usage of the name ironwood in English ma ...

, desert ironwood, or palo fierro in Spanish. It is the only species in the

monotypic genus In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispe ...

''Olneya''. This tree is part of the western

Sonoran Desert The Sonoran Desert () is a hot desert and ecoregion in North America that covers the northwestern Mexican states of Sonora, Baja California, and Baja California Sur, as well as part of the Southwestern United States (in Arizona and California). It ...

in Mexico and United States.

Description

The desert ironwood grows as a bush or

, reaching heights of about and average trunk diameters of about . Exceptionally, in larger protected washes it can reach greater height and a more massive trunk. In younger trees, the bark is gray, shiny, and smooth; in older trees the bark is broken open. The tree is

evergreen In botany, an evergreen is a plant which has Leaf, foliage that remains green and functional throughout the year. This contrasts with deciduous plants, which lose their foliage completely during the winter or dry season. Consisting of many diffe ...

, but can lose its

leaves A leaf (: leaves) is a principal appendage of the stem of a vascular plant, usually borne laterally above ground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, stem, ...

if temperatures fall below . In continual drought conditions the leaves will be lost. The leaves are bluish-green and pinnately compound. They are arranged on a petiole, long, with 6–9 leaflets (or variously up to 15, with 7 opposite and one terminal), each measuring . At the base of each pinnate leaf petiole grow two thorns, each about long. Bloom time occurs in late April/May to June. Flowers are of 5 unequal petals, in colors of medium purple, magenta-red, or white to pale pink. Seedpods are long and light reddish brown when seedpods have ripened. Two other species, '' Parkinsonia florida'' (blue palo verde) and '' Acacia constricta'' (catclaw acacia), have similar light red/brownish seedpods. Catclaw acacia's seedpods are shorter and .

Taxonomy

The genus name of ''Olneya'' is in honour of Stephen Thayer Olney (1812–1878), who was an American manufacturer and

botanist Botany, also called plant science, is the branch of natural science and biology studying plants, especially Plant anatomy, their anatomy, Plant taxonomy, taxonomy, and Plant ecology, ecology. A botanist or plant scientist is a scientist who s ...

with expertise in the genus ''

Carex ''Carex'' is a vast genus of over 2,000 species of grass-like plants in the family (biology), family Cyperaceae, commonly known as sedges (or seg, in older books). Other members of the family Cyperaceae are also called sedges, however those of ge ...

''. The genus was circumscribed by

Asa Gray Asa Gray (November 18, 1810 – January 30, 1888) is considered the most important American botany, botanist of the 19th century. His ''Darwiniana'' (1876) was considered an important explanation of how religion and science were not necessaril ...

in Pl. Nov. Thurb. page 328 in 1854.

Distribution and habitat

The species is native to the

Southwestern United States The Southwestern United States, also known as the American Southwest or simply the Southwest, is a geographic and cultural list of regions of the United States, region of the United States that includes Arizona and New Mexico, along with adjacen ...

and extreme northwestern Mexico in the Baja California Peninsula and the

. Within Mexico its range includes the states of

Baja California Sur Baja California Sur, officially the Free and Sovereign State of Baja California Sur, is a state in Mexico. It is the 31st and last state to be admitted, in 1974. It is also the second least populated Mexican state and the ninth-largest state by ...

and

Baja California Baja California, officially the Free and Sovereign State of Baja California, is a state in Mexico. It is the northwesternmost of the 32 federal entities of Mexico. Before becoming a state in 1952, the area was known as the North Territory of B ...

, on the

Gulf of California The Gulf of California (), also known as the Sea of Cortés (''Mar de Cortés'') or Sea of Cortez, or less commonly as the Vermilion Sea (''Mar Vermejo''), is a marginal sea of the Pacific Ocean that separates the Baja California peninsula from ...

side east of the cordillera ranges, and

Sonora Sonora (), officially Estado Libre y Soberano de Sonora (), is one of the 31 states which, along with Mexico City, comprise the Administrative divisions of Mexico, Federal Entities of Mexico. The state is divided into Municipalities of Sonora, 72 ...

state west of the

Sierra Madre Occidental The Sierra Madre Occidental is a major mountain range system of the North American Cordillera, that runs northwest–southeast through northwestern and western Mexico, and along the Gulf of California. The Sierra Madre is part of the American C ...

cordillera, in the south approaching the northern border of northern

Sinaloa Sinaloa (), officially the (), is one of the 31 states which, along with Mexico City, compose the Federal Entities of Mexico. It is divided into 18 municipalities, and its capital city is Culiacán Rosales. It is located in northwest Mexic ...

state. In the Southwestern US its range includes the

Colorado Desert The Colorado Desert is a part of the larger Sonoran Desert located in California, United States, and Baja California, Mexico. It encompasses approximately , including the heavily irrigated Coachella, Imperial and Mexicali valleys. It is home to ...

of southeast

Southern California Southern California (commonly shortened to SoCal) is a geographic and Cultural area, cultural List of regions of California, region that generally comprises the southern portion of the U.S. state of California. Its densely populated coastal reg ...

, a part of the Sonoran Desert, and western and southern

Arizona Arizona is a U.S. state, state in the Southwestern United States, Southwestern region of the United States, sharing the Four Corners region of the western United States with Colorado, New Mexico, and Utah. It also borders Nevada to the nort ...

. ''Olneya'' does not range into the higher-elevation, colder, southeast of Arizona's Sonoran Desert region, nor into the

sky island Sky islands are isolated mountains surrounded by radically different lowland environments. The term originally referred to those found on the Mexican Plateau and has extended to similarly isolated high-elevation forests. The isolation has s ...

s of the

Madrean Sky Islands The Madrean Sky Islands are enclaves of Madrean pine–oak woodlands, found at higher elevations in a complex of small mountain ranges in southern and southeastern Arizona, southwestern New Mexico, and northwestern Mexico. The sky islands are su ...

region.

Ecology

The pleasant-tasting sap is consumed by bees and hummingbirds. The

silky-flycatcher The silky-flycatchers are a small family, Ptiliogonatidae, of passerine birds. The family contains only four species in three genera. They were formerly lumped with waxwings and hypocolius in the family Bombycillidae, and they are listed in that ...

or '' phainopepla'' pose a problem, for when they consume mistletoe berries and excrete them in the cracks of ''Olneya tesota'', the mistletoe will parasitize its host.

An indicator species

''Olneya tesota'' is an

indicator species A bioindicator is any species (an indicator species) or group of species whose function, population, or status can reveal the qualitative status of the environment. The most common indicator species are animals. For example, copepods and other sma ...

of the Sonoran Desert region. The Sonoran Desert has one other species with the identical north–south, and east–west range. The seasonally migrating lesser long-nosed bat follows the bloom season of various species from south to north and extends into the same regions of the Sonoran Desert as ''Olneya''. The bat ranges from southern Baja California del Sur and north into the Southwestern US. In the north, both species define the Colorado Desert sub-region of the Sonoran Desert surrounding the northern end of the Gulf of California; further south in the Baja Peninsula the sub-division is defined as the Vizcaino Desert. The winter and permanent range of the bat extend into the northern countries of

Central America Central America is a subregion of North America. Its political boundaries are defined as bordering Mexico to the north, Colombia to the southeast, the Caribbean to the east, and the Pacific Ocean to the southwest. Central America is usually ...

Uses

The seeds can be eaten by first being roasted. ''Olneya'' ironwood is very hard and heavy. Its density is greater than water and thus sinks; it does not float downstream in washes and must be moved by current motion. Due to its considerable hardness, processing desert ironwood is difficult. Final treatment of the wood with solutions can also be difficult because of its high density. As a result, mass processing of this wood is difficult, and most of its commercial usages are artisanal, such as durable wooden sculptures as well as

knife A knife (: knives; from Old Norse 'knife, dirk') is a tool or weapon with a cutting edge or blade, usually attached to a handle or hilt. One of the earliest tools used by humanity, knives appeared at least Stone Age, 2.5 million years ago, as e ...

handles.

Culture

Ironwood Forest National Monument Ironwood Forest National Monument is located in the Sonoran Desert of Arizona. Created by Bill Clinton by Presidential Proclamation 7320 on June 9, 2000, the monument is managed by the Bureau of Land Management, an agency within the United State ...

in south-central Arizona is named for ''O. tesota''.

References

External links

Calflora Database: ''Olneya tesota'' (desert ironwood, ironwood)

USDA Plants Profile of ''Olneya tesota'' (desert ironwood)

UC Photos gallery – ''Olneya tesota''
* Lesser Long-nosed Bat Ranges – equal to ''Olneya tesota'':
Journey of the Nectar Bats

Learner.org: Map of Lesser Long-nosed Bat range

– ''article''. {{Taxonbar, from1=Q675377, from2=Q17432385 Robinieae Monotypic Fabaceae genera Trees of Northern America Flora of the California desert regions Flora of the Sonoran Deserts Natural history of the Colorado Desert