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Ambrosia acanthicarpa

ANNUAL BUR-SAGE


Higher Taxonomy
Family: Asteraceae (Compositae)View DescriptionDichotomous Key
Common Name: SUNFLOWER FAMILY
Habit: Annual to tree. Leaf: basal and/or cauline, alternate, opposite, rarely whorled, simple to 2+ × compound. Inflorescence: 1° inflorescence a head, resembling a flower, of several types (see below), 1--many in generally +- cyme-like cluster; each head generally with +- calyx-like involucre of 1--many series of phyllaries (involucre bracts); receptacle of head flat to conic or columnar, paleate (bearing paleae = receptacle bracts) or epaleate; flowers 1--many per head. Flower: bisexual, unisexual, or sterile, +- small, of several types (see below); calyx 0 or modified into +- persistent pappus of bristles, scales, and/or awns; corolla radial or bilateral (0), lobes generally (0)3--5; stamens 4--5, filaments generally free, generally fused to corolla at tube/throat junction, anthers generally fused into cylinder around style, anther base generally rounded or cordate (deeply sagittate or with tail-like appendages), tip (= flattened appendage) generally projecting beyond pollen sac; pistil 1, 2-carpeled, ovary inferior, 1-chambered, 1-seeded, placenta basal, style 1, tip generally +- 2-branched (except in some staminate disk flowers), branch tips truncate or generally bearing +- brush-like appendages; stigmas 2, generally on adaxial faces of style branches. Fruit: achene (also called a cypsela) (drupe in Chrysanthemoides), cylindric to ovoid, sometimes compressed, generally deciduous with pappus attached.
Genera In Family: +- 1500 genera, 23000 species: worldwide, many habitats. Note: Flower and head types differ in form and sexual condition. A disk flower has a generally radial corolla, with a cylindric tube, expanded throat, and generally 5 lobes. Disk flowers are generally bisexual and fertile but occasionally staminate with reduced ovaries. Discoid heads comprise only disk flowers. A radiant head is a variant of a discoid head, with peripheral disk flower corollas expanded, often bilateral. A ray flower corolla is bilateral, generally with a slender tube and flattened petal-like ray (single lip composed of generally 3 lobes). Ray flowers are generally pistillate or sterile (occasionally lacking styles). Radiate heads have peripheral ray flowers and central disk flowers. Disciform heads superficially resemble discoid heads, with pistillate or sterile flowers that lack rays, together with or separate from disk flowers. A ligulate flower is bisexual, with a bilateral, generally ephemeral corolla and 5-lobed ligule. Liguliflorous heads comprise only ligulate flowers. See glossary p. 31 for illustrations of family characteristics. Echinops sphaerocephalus L., Gaillardia aristata Pursh, Gaillardia pulchella Foug., Hymenothrix loomisii S.F. Blake, Tagetes erecta L., Thelesperma megapotamicum (Spreng.) Kuntze are waifs. Melampodium perfoliatum Kunth, historic urban waif. Ageratum conyzoides L., Guizotia abyssinica (L. f.) Cass., Santolina chamaecyparisus L., orth. var. are rare or uncommon escapes from cultivation. Dyssodia papposa, Ismelia carinata (Schousb.) Sch. Bip. [Chrysanthemum carinatum Schousb.], Mantisalca salmantica (L.) Briq. & Cavill. are historical or extirpated waifs in California. Inula helenium L. not documented in California. Taxa of Aster in TJM (1993) treated here in Almutaster, Doellingeria, Eurybia, Ionactis, Oreostemma, Sericocarpus, Symphyotrichum; Chamomilla in Matricaria; Bahia in Hymenothrix; Cnicus in Centaurea; Conyza in Erigeron and Laennecia; Dugaldia in Hymenoxys; Erechtites in Senecio; Hymenoclea in Ambrosia; Lembertia in Monolopia; Osteospermum ecklonis in Dimorphotheca; Picris echioides in Helminthotheca; Prionopsis in Grindelia; Raillardiopsis in Anisocarpus and Carlquistia; Schkuhria multiflora in Picradeniopsis; Trimorpha in Erigeron; Venidium in Arctotis; Viguiera in Aldama and Bahiopsis; Whitneya in Arnica. Amauriopsis in TJM2 (2012) treated here in Hymenothrix; Arida in Leucosyris; Bahia in Picradeniopsis; Eucephalus in Doellingeria.
Unabridged Note: Largest family of vascular plants in California and of eudicots globally.
eFlora Treatment Author: David J. Keil, except as noted
Scientific Editor: David J. Keil, Bruce G. Baldwin.
Genus: AmbrosiaView DescriptionDichotomous Key


Common Name: RAGWEED, BUR-SAGE, BURROBRUSH
Habit: Annual to small tree; monoecious. Leaf: simple, opposite or alternate, generally petioled, entire to 1--4-pinnately lobed or divided, distal-most often reduced, bract-like. Inflorescence: staminate heads and pistillate heads together in distal leaf axils or in terminal, spike-like clusters, or staminate heads in spike- or raceme-like clusters distal to pistillate heads; staminate involucre +- cup-shaped, phyllaries in 1 series, +- fused, receptacle flat or rounded, paleate; pistillate phyllaries 0 or few, in 1 series, free, +- thin, receptacle paleate, palea bases fused, becoming a hard bur with each pistillate flower in a separate chamber, tips (occasionally not evident in flower heads) becoming hard knobs, spines, or scarious wings. Staminate Flower: 3--many; corolla translucent to yellow or red-purple; filaments fused, anthers free; style unbranched, ovary vestigial, pappus 0. Pistillate Flower: 1--5; corolla 0; style branches elongated. Fruit: inside bur with beak(s) surrounding style(s); pappus 0.
Etymology: (Greek: early name for aromatic plants; mythic food of the gods) Note: Wind-blown pollen often allergenic.
Unabridged Note: Spines of bur derived from paleae, not phyllaries.
eFlora Treatment Author: David J. Keil
Reference: Strother 2006 FNANM 21:10--18
Ambrosia acanthicarpa Hook.
NATIVE
Habit: Annual 4--15 dm, from slender taproot; herbage +- canescent-strigose, +- bristly. Stem: 1--several from base, branches ascending. Leaf: proximally opposite, petiole 1--6+ cm; blade 1--8 cm, +- deltate, shallowly lobed to generally 1--3 × pinnately divided. Inflorescence: staminate heads few to generally many in raceme-like clusters, 2--5 mm diam, phyllaries 3--9, tips of longest 3 +- black-lined along midvein, strigose, occasionally bristly; pistillate heads 1-flowered, sessile, clustered in distal (occasionally also proximal) leaf axils. Fruit: bur 5--7 mm, ovoid, +- golden or dark purple, glabrous or puberulent; spines 0--30, spiraled, proximally flattened, straight, sharp. Chromosomes: 2n=36.
Ecology: Sandy plains, disturbed sites, many communities; Elevation: -30--2450 m. Bioregional Distribution: NCoR, SN, SnJV, CW, SW, GB, D; Distribution Outside California: to southern Canada, Michigan, Missouri, Texas, northwestern Mexico. Flowering Time: Jul--Dec
Synonyms: Franseria acanthicarpa (Hook.) Coville
Jepson eFlora Author: David J. Keil
Reference: Strother 2006 FNANM 21:10--18
Index of California Plant Names (ICPN; linked via the Jepson Online Interchange)

Previous taxon: Ambrosia
Next taxon: Ambrosia ambrosioides

Botanical illustration including Ambrosia acanthicarpabotanical illustration including Ambrosia acanthicarpa


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Citation for this treatment: David J. Keil 2012, Ambrosia acanthicarpa, in Jepson Flora Project (eds.) Jepson eFlora, https://ucjeps.berkeley.edu/eflora/eflora_display.php?tid=803, accessed on December 03, 2024.

Citation for the whole project: Jepson Flora Project (eds.) 2024, Jepson eFlora, https://ucjeps.berkeley.edu/eflora/, accessed on December 03, 2024.

Ambrosia acanthicarpa
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©2008 Keir Morse
Ambrosia acanthicarpa
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©2014 Keir Morse
Ambrosia acanthicarpa
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©2014 Keir Morse
Ambrosia acanthicarpa
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©2014 Keir Morse
Ambrosia acanthicarpa
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©2014 Keir Morse

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Geographic subdivisions for Ambrosia acanthicarpa:
NCoR, SN, SnJV, CW, SW, GB, D
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map of distribution 1

(Note: any qualifiers in the taxon distribution description, such as 'northern', 'southern', 'adjacent' etc., are not reflected in the map above, and in some cases indication of a taxon in a subdivision is based on a single collection or author-verified occurrence).






 

Data provided by the participants of the  Consortium of California Herbaria.

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Blue markers indicate specimens that map to one of the expected Jepson geographic subdivisions (see left map). Purple markers indicate specimens collected from a garden, greenhouse, or other non-wild location.
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CCH collections by month Flowering-Fruiting Monthly Counts

Duplicates counted once; synonyms included.
Species do not include records of infraspecific taxa, if there are more than 1 infraspecific taxon in CA.
Blue line denotes eFlora flowering time (fruiting time in some monocot genera).