Ambrosia deltoidea

(Rabbit Bush, Triangle Burr Ragweed, Triangle Bursage, Triangle Leaf Bursage)

Conservation Status

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Population Analysis

For the 835,580 species in the Class Magnoliopsida (Dicotyledons), we average 4.30 observations each in our database; for the Triangle Leaf bursage, we have 245 observations. Compared to other species in this Class, this species is moderately common.
A two-sample t-test can be used to determine whether the trend in observations of the Triangle Leaf bursage is the same as the trend in observations of Magnoliopsida. Is this species just as common, as a proportion of all observations, as it once was? The answer is no, changes in observation rate of this species significantly differ from changes in observation rate of its Class. (t=4.869, p<0.001)
How do observation rates of the Triangle Leaf bursage differ from those of Magnoliopsida? To answer this, we examined the percentage of observerations for Magnoliopsida that were observations of the Triangle Leaf bursage each year. We then correlated this percentage with observation year. If observations of the Triangle Leaf bursage are becoming more common relative to other species of Magnoliopsida, the correlation should be positive, but if it is becoming less common, the correlation should be negative. In fact, the correlation is positive (r=.06), with a positive slope (m = .0001), suggesting that the Triangle Leaf bursage may be increasing relative to other species of Magnoliopsida. This correlation is statistically significant. (F = 7.34, p<.05)
The scatter chart to the right shows the percentage of all observations for Magnoliopsida each year that were observations of the Triangle Leaf bursage.

Taxonomy

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Kingdom: Plantae - Plants
- Phylum: Tracheophyta - Vascular Plants
  - Class: Magnoliopsida - Dicotyledons
    - Order: Asterales
      - Family: Noctuoidea
        Subfamily: Asteroideae
        Tribe: Heliantheae
        Genus: Ambrosia (am-BRO-zhuh) Linnaeus, Sp. Pl. 2: 987. 1753; Gen. Pl. ed. 5, 425. 1754. - Ragweed [Greek ambrosia, "food of the gods," allusion unclear]
        Specific epithet: deltoidea (Torr.) Payne
        Botanical name: Ambrosia deltoidea (Torr.) Payne

Unambiguous Synonyms:

Franseria confertiflora (DC.) Rydb.
Franseria deltoidea Torrey, Smithsonian Contr. Knowl. 6(2): 15. 1853
Franseria strigulosa Rydb.
Gaertneria tenuifolia Harvey & Gray

Notes:

Name Status: Accepted Name. Latest taxonomic scrutiny: 15-Mar-2000

Place of publication: J. Arnold Arbor. 45:421. 1964

Name verified on 29-Oct-2007 by ARS Systematic Botanists. Last updated: 29-Oct-2007

Physical Description

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Tribe Asteroideae:

The Heliantheae are a tribe of closely related genera of the sunflower family that can be readily recognized due to the association of a receptacular bract or chaff scale with each disk floret in the head. The heads usually include bisexual, actinomorphic disk florets with tubular corollas that have 4 or 5 distal lobes and also peripheral zygomorphic female or sometimes sterile florets with strap-shaped corollas that have 3 or fewer distal teeth. However, the ray flowers are sometimes absent and the heads are then discoid, containing only bisexual florets with tubular corollas. The pappus is absent or more commonly ranges from scales to stiff bristles. -- Gerald Carr.

Genus Ambrosia:

Annuals, perennials, or shrubs, 10-400+ cm (usually rhizomatous). Stems erect, decumbent, or prostrate, branched. Leaves usually cauline; opposite ± throughout or opposite (proximal) and alternate or mostly alternate; sessile or petiolate; blades (or lobes) deltate, elliptic, filiform, lanceolate, linear, obovate, ovate, or rhombic (and most intermediate shapes), usually pinnately, sometimes palmately lobed, ultimate margins entire or toothed, faces hairy or glabrate, usually gland-dotted or stipitate-glandular. Heads discoid (unisexual, pistillate proximal to or intermixed with staminates, staminates usually in racemiform to spiciform arrays; rarely, single plants all or mostly staminate or pistillate). Pistillate heads: phyllaries 12-30(-80+) in 1-8+ series, outer (1-) 5-8 distinct or ± connate, herbaceous, the rest (sometimes interpreted as paleae) ± connate, usually with free tips forming tubercles, spines, or wings (the whole becoming a hard perigynium or "bur") ; florets 1(-5+), corollas 0. Staminate heads: involucres cup-shaped to saucer-shaped, 1.5-6+ mm diam.; phyllaries 5-16+ in ± 1 series, ± connate; receptacles ± flat or convex; paleae spatulate to linear, membranous, sometimes villous, hirtellous, and/or gland-dotted or stipitate-glandular, sometimes none; florets 5-60+; corollas whitish or purplish, ± funnelform, lobes 5, erect or incurved; staminal filaments connate, anthers distinct or weakly coherent. Cypselae (black) ± ovoid or fusiform, enclosed within globose to obovoid, pyramidal, pyriform, obconic, or fusiform, hard, smooth, tuberculate, spiny, or winged "burs"; pappi 0. x = 18.

Species 40+: tropical to subtropical and temperate New World, mostly North America, some established in Old World.^[1]

Species Ambrosia deltoidea:

Shrubs, 30-80+ cm. Stems erect. Leaves mostly alternate; petioles 5-12+ mm; blades deltate to lance-deltate, 12-25(-35) × 5-12(-18) mm, bases cuneate to truncate, margins toothed, abaxial faces ± densely tomentulose (between veins), adaxial faces sparsely tomentulose, glabrescent. Pistillate heads clustered, proximal to staminates; florets 2-3. Staminate heads: peduncles 0.5-3(-5) mm; involucres ± cup-shaped, 4-8 mm diam., tomentulose; florets 12-30+. Burs: bodies ± fusiform to globose, 3-4 mm, usually stipitate-glandular (little, if at all, tomentulose), spines 20-30+, scattered or on distal 1/2, ± subulate (the proximal basally flattened), 1-3 mm, tips usually straight, sometimes uncinate. 2n = 36. [source]

Some specimens are intermediate for the char-acteristics that distinguish Ambrosia deltoidea and A. chenopodiifolia. The type of A. deltoidea may be better treated as conspecific with that of A. chenopodiifolia. [source]

Habit: Subshrub, Shrub

Flowers: Bloom Period: February, March, April, May. • Flower Color: inconspicuous, none

Distribution

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Range and Population

North America

Native: Sonora.

Habitat

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Sandy washes, benches; 200-1000 m^[2].

Reproduction

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Duration: Perennial

Growth

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Culture: Space 18-24" apart.

Sunlight: Sun Exposure: Full Sun.

Moisture: Drought Tolerance: High

Temperature: Cold Hardiness: 9a, 9b, 10a, 10b. (map)

Similar Species

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Members of the genus Ambrosia:

Bibliography

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Ambrosia (Compositae). J. Arnold Arbor. 45: 401430.
FNA Editorial Committee. 1993–. Flora of North America. (F NAmer)
Payne, W. W. 1964. A re-evaluation of the genus
Payne, W. W. 1964. A re-evaluation of the genus Ambrosia (Compositae). J. Arnold Arbor. 45:421.
Peterson, K. M. and W. W. Payne. 1973. The genus Hymenoclea (Compositae: Ambrosieae). Brittonia 25: 243256.
Strother, J. L. and B. G. Baldwin. 2002. Hymenocleas are ambrosias (Compositae). Madroño 49: 143144.
Wiggins, I. L. 1980. Flora of Baja California. (F Baja)

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Notes

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Contributors:

"Ambrosia deltoidea". in Flora of North America Vol. 21 Page 11, 14. Published by Oxford University Press. Online at EFloras.org.
Bisby FA, Roskov YR, Orrell TM, Nicolson D, Paglinawan LE, Bailly N, Kirk PM, Bourgoin T, van Hertum J, eds (2008). Species 2000 & ITIS Catalogue of Life: 2008 Annual Checklist Taxonomic Classification. CD-ROM; Species 2000: Reading, U.K.
Global Biodiversity Information Facility. Accessed February 16, 2008. http://www.gbif.org Mediated distribution data from 4 providers.
USDA, ARS, National Genetic Resources Program. Germplasm Resources Information Network - (GRIN) [Online Database]. National Germplasm Resources Laboratory, Beltsville, Maryland. URL (April 25, 2008)

Data Sources:

Accessed through GBIF Data Portal February 16, 2008:

Missouri Botanical Garden, Missouri Botanical Garden
School of Life Sciences, Arizona State University, Arizona State University Vascular Plant Herbarium
USDA PLANTS, USDA PLANTS Database
Utah State University, USU-UTC Specimen Database

Identifiers:

Integrated Taxonomic Information System (ITIS) Taxonomic Serial Number (TSN): 36505
Global Biodiversity Information Facility Taxonkey: 13749036
Globally Unique Identifier: urn:lsid:ipni.org:names:176077-1
Natural Heritage Network Species Identifier: PDAST0C0C0
U.S.D.A. Plant Symbol: AMDE4
Zipcode Zoo Species Identifier: 20779

Footnotes:

John L. Strother "Ambrosia". in Flora of North America Vol. 21 Page 3, 9, 10, 25. Oxford University Press. Online at EFloras.org.
"Ambrosia deltoidea". in Flora of North America Vol. 21 Page 11, 14. Oxford University Press. Online at EFloras.org.

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Last Revised: May 11, 2008