''Vachellia constricta'', also known commonly as the whitethorn acacia, is a

shrub A shrub or bush is a small to medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from trees by their multiple ...

native to

Mexico Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...

and 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 ...

.USDA FEIS data
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Distribution

In the Southwest ''V. constricta'' grows in the southern half of

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 ...

, extending into

New Mexico New Mexico is a state in the Southwestern United States, Southwestern region of the United States. It is one of the Mountain States of the southern Rocky Mountains, sharing the Four Corners region with Utah, Colorado, and Arizona. It also ...

and

West Texas West Texas is a loosely defined region in the U.S. state of Texas, generally encompassing the desert climate, arid and semiarid climate, semiarid lands west of a line drawn between the cities of Wichita Falls, Texas, Wichita Falls, Abilene, Texa ...

. It grows in Mexico as far south as

Oaxaca Oaxaca, officially the Free and Sovereign State of Oaxaca, is one of the 32 states that compose the political divisions of Mexico, Federative Entities of the Mexico, United Mexican States. It is divided into municipalities of Oaxaca, 570 munici ...

, with small disjunct populations in

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 ...

and in the Magdalena Plain 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 ...

. In the

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 ...

, ''Vachellia constricta'' grows in arroyos and washes, where it blooms in late spring (April–May), with a second round of blooms in July–October. Blooming requires a minimum amount of rain, followed by a period of warmth.

Description

''Vachellia constricta'' typically grows to in height, occasionally reaching . Its stems range from a light gray to a mahogany color, with pairs of straight white spines anywhere from 0.5 to 2 cm long. The small leaves are even-

pinnate Pinnation (also called pennation) is the arrangement of feather-like or multi-divided features arising from both sides of a common axis. Pinnation occurs in biological morphology, in crystals, such as some forms of ice or metal crystals, and ...

, usually 2.5–4 cm in length, with each of the 3–9 pairs of pinnae made of 4–16 pairs of leaflets, which are about 3.5 mm long and 1 mm wide. The flowers occur in small yellow balls about 1 cm in diameter. The flowers offer no nectar and little pollen, and so tend to have few visitors.

Extrafloral nectaries Nectar is a viscous, sugar-rich liquid produced by plants in glands called nectaries, either within the flowers with which it attracts pollinating animals, or by extrafloral nectaries, which provide a nutrient source to animal mutualists, ...

grow along the main stem of the compound leaves and attract ants to the trees. The seed pods are relatively long and thin, up to 12 cm long but only 3–6 mm wide. The leaves may drop in response to either dryness or cold. Image:Acacia constricta pods.jpg, ''Vachellia constricta'' seed pods

Varieties

Cultivation

''Vachellia constricta'' is cultivated by specialty

plant nurseries A nursery is a place where plants are propagated and grown to a desired size. Mostly the plants concerned are for gardening, forestry, or conservation biology, rather than agriculture. They include retail nurseries, which sell to the general ...

as an

ornamental plant Ornamental plants or ''garden plants'' are plants that are primarily grown for their beauty but also for qualities such as scent or how they shape physical space. Many flowering plants and garden varieties tend to be specially bred cultivars th ...

. It is used in

native plant In biogeography, a native species is indigenous to a given region or ecosystem if its presence in that region is the result of only local natural evolution (though often popularised as "with no human intervention") during history. The term is equi ...

desert habitat gardens. It can be trained as a small tree or grown as a barrier

hedge A hedge or hedgerow is a line of closely spaced (3 feet or closer) shrubs and sometimes trees, planted and trained to form a barrier or to mark the boundary of an area, such as between neighbouring properties. Hedges that are used to separate ...

References

General references

* Raymond M. Turner, Janice E. Bowers, and Tony L. Burgess, ''Sonoran Desert Plants: an Ecological Atlas'' (Tucson: The University of Arizona Press, 1995) pp. 15–16

External links

USDA Plants profile: ''Vachellia constricta'' (as ''Acacia constricta'')

Lady Bird Johnson Wildflower Center
{{Taxonbar, from=Q4670902 constricta Flora of the South-Central United States Flora of Arizona Flora of Mexico Flora of the Sonoran Deserts North American desert flora Flora of Virginia Flora without expected TNC conservation status