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Ambrosia deltoidea

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

Common Names

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Common Names in English:

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

Description

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Tribe Heliantheae

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

Physical Description

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

Size/Age/Growth

Size: 18-24" tall.

Habitat

Sandy washes, benches; 200-1000 m (Ref. 51609).

Biology

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Reproduction

Duration: Perennial

Growth

Culture: Space 18-24" apart.

Sunlight: Sun Exposure: Full Sun .

Moisture: Drought Tolerance: High

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

Taxonomy

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Unambiguous Synonyms

  1. Ambrosia deltoidea (Torr.) Payne
  2. Ambrosia deltoidea Torr.
  3. Franseria confertiflora (DC.) Rydb.
  4. Franseria deltoidea Torrey, Smithsonian Contr. Knowl. 6(2): 15. 1853
  5. Franseria strigulosa Rydb.
  6. 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

Similar Species

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Members of the genus Ambrosia

There are approximately 132 species in this genus. Here are just 100 of them:

A. abrotanifolia · A. absynthyfolia · A. acanthicarpa (Annual Bursage) · A. acanthocarpa · A. acuminata · A. ambrosioides (Ambrosia Bursage) · A. ambrosioides septentrionale · A. ambrosioides subsp. septentrionale · A. arborescens · A. artemesiifolia · A. artemisiaefolia · A. artemisifolia (Common Ragweed) · A. artemisiifolia (Annual Bur-Sage Ambrosia Artemisiifolia) · A. artemisiifolia f. gracilissima · A. artemisiifolia f. villosa · A. artemisiifolia L. var. artemisiifolia L. (Ragweed) · A. artemisiifolia L. var. elatior (L.) Descourtils · A. artemisiifolia L. var. paniculata (Michx.) Blank. (Annual Ragweed) · A. artemisiifolia subsp. diversifolia · A. artemisiifolia var. artemisiifolia · A. artemisiifolia var. elatior (Annual Ragweed) · A. artemisiifolia var. jamaicensis · A. artemisiifolia var. octocornis · A. artemisiifolia var. paniculata (Annual Ragweed) · A. artemisiifolia var. quadricornis · A. artemisiifolia var. trinitensis · A. artemisioides · A. artemissifolia · A. artimisiifolia · A. aspera · A. bidentata (Lance-Leaf Ragweed) · A. bipinnatifida · A. bryantii · A. camphorata · A. canescens (Hairy Ragweed) · A. carduacea · A. caudata · A. chamissomis · A. chamissonis (Beach-Bur) · A. chamissonis f. bipinnatisecta · A. chamissonis var. cuneifolia · A. cheiranthifolia (Rio Grande Ragweed) · A. chenopodiifolia (San Diego Ambrosia) · A. chilensis · A. confertiflora (Ragweed) · A. cordifolia (Heartleaf Bursage) · A. coronopifolia · A. crithmifolia · A. deltoidea (Rabbit Bush) · A. dentata · A. divaricata · A. diversifolia · A. dumosa (Burro Bush) · A. elata · A. elatior f. aurea · A. elatior var. artemisiifolia · A. elatior var. elatior · A. elatior var. heterophylla · A. eliator · A. eriocentra (Hollyleaf Bursage) · A. flexuosa · A. fruticosa · A. fruticosa var. canescens · A. fruticosa var. intermedia · A. grayi (Bur Ragweed) · A. helenae (Helen Ragweed) · A. heterophylla · A. hispida (Coastal Ragweed) · A. humilis · A. ilicifolia (Holly-Leaf Bursage) · A. incisa · A. integrifolia · A. intergradiens (Intergrading Ragweed) · A. johnstoniorum · A. lindheimeriana · A. linearis (Linear-Leaf Bursage) · A. longifolia · A. longistylis · A. magdalenae · A. maritima · A. media · A. mexicana · A. microcephala · A. monogyra · A. nivea · A. orobanchifera · A. palustris · A. paniculata f. dissecta · A. paniculata f. litoralis · A. paniculata var. abrotanifolia · A. paniculata var. cumanensis · A. paniculata var. peruviana · A. pannosa · A. parvifolia · A. peruviana (Peruvian Ragweed) · A. pitcheri · A. polystachya · A. psilostachya (Cuman Ragweed) · A. psilostrachya · A. pumila (Dwarf Burr Ragweed)

Bibliography

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More Info

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Notes

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Contributors

Data Sources

Accessed through GBIF Data Portal February 16, 2008:

Identifiers

Footnotes

Last Revised: 2008-08-11