''Ambrosia deltoidea'' is a North American species of flowering plant in the family

Asteraceae The family Asteraceae, alternatively Compositae, consists of over 32,000 known species of flowering plants in over 1,900 genera within the order Asterales. Commonly referred to as the aster, daisy, composite, or sunflower family, Compositae w ...

known by the common names triangle bur ragweed, triangle bursage, and triangleleaf bursage.

Distribution

The plant is native to the

Sonoran Desert The Sonoran Desert ( es, Desierto de Sonora) is a desert in North America and ecoregion that covers the northwestern Mexican states of Sonora, Baja California, and Baja California Sur, as well as part of the southwestern United States (in Ariz ...

region of North America, where it can be found in

Baja California Baja California (; 'Lower California'), officially the Free and Sovereign State of Baja California ( es, Estado Libre y Soberano de Baja California), is a state in Mexico. It is the northernmost and westernmost of the 32 federal entities of Mex ...

, Baja California Sur, and Sonora in

Mexico Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...

, with its distribution extending north into

Arizona Arizona ( ; nv, Hoozdo Hahoodzo ; ood, Alĭ ṣonak ) is a state in the Southwestern United States. It is the 6th largest and the 14th most populous of the 50 states. Its capital and largest city is Phoenix. Arizona is part of the Fou ...

in the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...

.Marshall, K. Anna. 1994
''Ambrosia deltoidea''.
In: Fire Effects Information System, nline U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory. This shrub grows in desert habitat, such as desert grasslands and

shrublands Spring Park is a small area in London, England. It is within the London Borough of Bromley and the London Borough of Croydon, straddling the traditional Kent-Surrey border along The Beck. Spring Park is located north of Addington, west of West ...

. It is a dominant or codominant species, and one of the most abundant plants,Bowers, J. E. (2002)
Regeneration of triangle-leaf bursage (''Ambrosia deltoidea'': Asteraceae): Germination behavior and persistent seed bank.
''The Southwestern Naturalist'' 47(3) 449-53. in the Arizona Upland Subdivision of the

. It may occur in upper and lower bajadas, but it is most often found in the

ecotone An ecotone is a transition area between two biological communities, where two communities meet and integrate. It may be narrow or wide, and it may be local (the zone between a field and forest) or regional (the transition between forest and gras ...

between them. It can be found in open areas. It grows on steep, rocky slopes alongside cacti such as the

saguaro The saguaro (, ) (''Carnegiea gigantea'') is a tree-like cactus species in the monotypic genus ''Carnegiea'' that can grow to be over tall. It is native to the Sonoran Desert in Arizona, the Mexican state of Sonora, and the Whipple Mountai ...

and

paloverde ''Parkinsonia'' , also ''Cercidium'' , is a genus of flowering plants in the pea family, Fabaceae. It contains about 12 species that are native to semi-desert regions of Africa and the Americas. The name of the genus honors English apothecary ...

such as the yellow paloverde. Other plants in the habitat include

condalia ''Condalia'' is a genus of spiny shrubs in the tribe Rhamneae of the buckthorn family, Rhamnaceae. It was named for Antonio Condal, an 18th Spanish physician. Members of the genus are native to tropical and subtropical deserts and xeric sh ...

ocotillo ''Fouquieria splendens'' (commonly known as ocotillo (), but also referred to as buggywhip, coachwhip, candlewood, slimwood, desert coral, Jacob's staff, Jacob cactus, and vine cactus) is a plant indigenous to the Sonoran Desert and Chihuahuan ...

jatropha ''Jatropha'' is a genus of flowering plants in the spurge family, Euphorbiaceae. The name is derived from the Greek words ἰατρός (''iatros''), meaning "physician", and τροφή (''trophe''), meaning "nutrition", hence the common name ...

, and prickly pears. The bursage easily invades grassland that has been overgrazed. Areas protected from grazing have less bursage.Payne, Willard William 1964. Journal of the Arnold Arboretum 45(4): plate IV (4), figures 30-34
line drawings of ''Ambrosia deltoidea''
figure captions on page 429
/ref>

Description

''Ambrosia deltoidea'' is a shrub growing from a

taproot A taproot is a large, central, and dominant root from which other roots sprout laterally. Typically a taproot is somewhat straight and very thick, is tapering in shape, and grows directly downward. In some plants, such as the carrot, the taproo ...

with many lateral and

adventitious root Important structures in plant development are buds, shoots, roots, leaves, and flowers; plants produce these tissues and structures throughout their life from meristems located at the tips of organs, or between mature tissues. Thus, a living plan ...

s. The plant produces many thin branches growing up to about half a meter tall. It generally has many dead branches tangled in the living crown. It is drought-deciduous. The leaves are no more than 2 centimeters long. The branches and new leaves are coated thinly in woolly fibers; the leaves become hairless with age. The

inflorescence An inflorescence is a group or cluster of flowers arranged on a Plant stem, stem that is composed of a main branch or a complicated arrangement of branches. Morphology (biology), Morphologically, it is the modified part of the shoot of sperma ...

is a spike of several

staminate The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filame ...

flower heads. There are often some

pistillate Gynoecium (; ) is most commonly used as a collective term for the parts of a flower that produce ovules and ultimately develop into the fruit and seeds. The gynoecium is the innermost whorl (botany), whorl of a flower; it consists of (one or m ...

heads just below these, with some pistillate heads borne on lateral branches. The fruit is an achene covered in spines. The achenes are usually dispersed when they stick to animals. The plant has been observed to have a lifespan of about 50 years.

Uses

This plant acts as a nurse plant for other species, providing shade and increased soil nitrogen for young growing plants. It also protects seedlings from

herbivory A herbivore is an animal anatomically and physiologically adapted to eating plant material, for example foliage or marine algae, for the main component of its diet. As a result of their plant diet, herbivorous animals typically have mouthpart ...

. It is the main nurse plant for saguaro in Organ Pipe National Monument. It also serves as nurse plant for yellow paloverde, ocotillo, and some prickly pear species. Most bursage plants are associated with a perennial plant. This plant is not palatable to mammals and it is not grazed by livestock. Airborne

allergen An allergen is a type of antigen that produces an abnormally vigorous immune response in which the immune system fights off a perceived threat that would otherwise be harmless to the body. Such reactions are called allergies. In technical terms ...

s from this plant can cause

contact dermatitis Contact dermatitis is a type of acute or chronic inflammation of the skin caused by exposure to chemical or physical agents. Symptoms of contact dermatitis can include itchy or dry skin, a red rash, bumps, blisters, or swelling. These rashes are ...

in humans.Schumacher, M. J. and N. G. Silvis. (2003)
Airborne contact dermatitis from ''Ambrosia deltoidea'' (triangle-leaf bursage).
''Contact Dermatitis'' 48(4) 212-16.

References

External links

Arizona-Sonora Desert Museum''Ambrosia deltoidea'' — Calphotos Photo Gallery, University of California
*[https://web.archive.org/web/20150911220440/http://www.dendro.cnre.vt.edu/dendrology/syllabus2/factsheet.cfm?ID=762 Virginia Tech vTree Fact Sheet, triangleleaf bursage Asteraceae ''Ambrosia deltoidea'' (Torr.) Payne]
Pollen Library, IMS Health, Triangle Burr-Ragweed (''Ambrosia deltoidea'')
{{Taxonbar, from=Q4741891 deltoidea Flora of the Sonoran Deserts Flora of Arizona Flora of Baja California Flora of Sonora Plants described in 1853 Taxa named by John Torrey