Jepson eFlora: Taxon page
Key to families | Table of families and genera
Previous taxon Index to accepted names and synonyms:
| A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z |
Next taxon
Ambrosia eriocentra
WOOLLY 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, Eucephalus, Eurybia, Ionactis, Oreostemma, Sericocarpus, Symphyotrichum; Chamomilla in Matricaria; 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 Bahia; Trimorpha in Erigeron; Venidium in Arctotis; Whitneya in Arnica. Taxa of Arida in TJM2 (2012) treated here in Leucosyris.
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.
Species In Genus: 45--50 species: native to America, especially southwestern United States, northern Mexico. 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 paleas, not phyllaries.

Ambrosia eriocentra (A. Gray) W.W. Payne
NATIVE
Habit: Shrub 3--18 dm, +- spheric. Stem: gray-brown, +- woolly, becoming glabrous. Leaf: sessile, 1--9 cm, +- lanceolate, base tapered, coarse-toothed or pinnately lobed, +- rolled under, abaxially gray-tomentose, minutely resin-gland-dotted, adaxially +- green, thinly tomentose, gland-dotted. Inflorescence: staminate heads few, in raceme-like clusters, 5--7 mm diam, phyllaries 5--8, long-soft hairy; pistillate heads generally 1-flowered, clustered in distal leaf axils. Fruit: bur 8--11 mm, green-brown, densely long-soft-hairy; spines 12--20, generally near middle, 3--4 mm, straight, flat, stout, sharp, tips +- hair-tufted. Chromosomes: 2n=36.
Ecology: Dry washes and slopes; Elevation: 450--1750 m. Bioregional Distribution: e DMoj, DMtns; Distribution Outside California: to northwestern Arizona, southwestern Utah. Flowering Time: Apr--Jun
eFlora Treatment Author: David J. Keil
Jepson Online Interchange

Previous taxon: Ambrosia dumosa
Next taxon: Ambrosia ilicifolia

Name Search
botanical illustration including Ambrosia eriocentra

Contact/Feedback

Citation for this treatment: David J. Keil 2016. Ambrosia eriocentra, in Jepson Flora Project (eds.) Jepson eFlora, http://ucjeps.berkeley.edu/cgi-bin/get_IJM.pl?tid=824, accessed on April 28, 2016.

Citation for the whole project: Jepson Flora Project (eds.) 2016. Jepson eFlora, http://ucjeps.berkeley.edu/IJM.html, accessed on April 28, 2016.


Ambrosia eriocentra
click for enlargement
© 2006 Steve Matson
Ambrosia eriocentra
click for enlargement
© 2010 James M. Andre
Ambrosia eriocentra
click for enlargement
© 2010 Neal Kramer
Ambrosia eriocentra
click for enlargement
© 2006 Steve Matson
Ambrosia eriocentra
click for enlargement
© 2010 Neal Kramer
Ambrosia eriocentra
click for enlargement
© 2010 Neal Kramer

More photos of Ambrosia eriocentra in CalPhotos


Geographic subdivisions for Ambrosia eriocentra:
e DMoj, DMtns;
Markers link to CCH specimen records. If the markers are obscured, reload the page [or change window size and reload]. Yellow markers indicate records that may provide evidence for eFlora range revision or may have georeferencing or identification issues.
READ ABOUT YELLOW FLAGS
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 occurence).

View elevation by latitude chart
Data provided by the participants of the Consortium of California Herbaria.
View all CCH records

CCH collections by month

Duplicates counted once; synonyms included.
Species do not include records of infraspecific taxa.
Blue line denotes eFlora flowering time.