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Vascular Plants of California
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Hazardia detonsa

Higher Taxonomy
Family: Asteraceae (Compositae)View DescriptionDichotomous Key
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; 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; Whitneya in Arnica. Amauriopsis in TJM2 (2012) treated here in Hymenothrix; Arida in Leucosyris; Bahia in Picradeniopsis.
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: HazardiaView DescriptionDichotomous Key

Habit: Perennial herb to shrub, generally resinous. Stem: 2--25 dm, leafy. Leaf: generally sessile or short-petioled. Inflorescence: heads radiate, disciform, or discoid; involucres cylindric or obconic to bell-shaped; phyllaries graduated in 5--9 series, linear to (ob)lanceolate, tips erect or generally recurved; receptacle flat, pitted, epaleate. Ray Or Pistillate Flower: 0 or [3]5--18[25]; corolla yellow or sometimes becoming red-purple, ray generally 2--9 mm (<= 1.8 mm in Hazardia cana). Disk Flower: 4--60; corolla 4--11 mm, gradually flared from middle, yellow, tinged red, or sometimes becoming red-purple. Fruit: 1--10 mm, 4--5-angled; pappus of 20--60 barbed bristles, 2.5--12 mm, white to red-brown.
Species In Genus: 13 species: western North America. Etymology: (Barclay Hazard, 19th century California botanist)
eFlora Treatment Author: David J. Keil, Gregory K. Brown & W.D. Clark
Reference: Clark 1979 Madroño 26:105--127; Clark 2006 FNANM 20:445--449
Unabridged Reference: Clark 1979 Madroño 26:105--127
Hazardia detonsa (Greene) Greene
Habit: Shrub 6--25 dm, +- densely woolly-tomentose. Leaf: 4--14 cm, (ob)ovate, thick, obtuse, +- serrate. Inflorescence: heads radiate or disciform; involucre 10--13 mm wide, +- bell-shaped; phyllaries 30--50, 4--10 mm, oblong, acute, +- densely tomentose. Ray Or Pistillate Flower: 6--14; corolla sometimes becoming red-purple, tube 5--6 mm, ray < 2.2 mm, not exceeding disk corolla. Disk Flower: 30--40; corolla 8--10 mm, sometimes becoming red-purple. Fruit: 3--4 mm, 4-ribbed, hairy; pappus 6--9 mm, (+- red) brown. Chromosomes: 2n=10.
Ecology: Open rocky slopes, sea cliffs, coastal scrub, chaparral, pine woodland; Elevation: < 450 m. Bioregional Distribution: n ChI. Flowering Time: Apr--Nov Note: Highly variable; hybridizes with Hazardia squarrosa var. grindelioides.
Jepson eFlora Author: David J. Keil, Gregory K. Brown & W.D. Clark
Reference: Clark 1979 Madroño 26:105--127; Clark 2006 FNANM 20:445--449
Index of California Plant Names (ICPN; linked via the Jepson Online Interchange)
Listed on CNPS Rare Plant Inventory

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Botanical illustration including Hazardia detonsa

botanical illustration including Hazardia detonsa


Citation for this treatment: David J. Keil, Gregory K. Brown & W.D. Clark 2012, Hazardia detonsa, in Jepson Flora Project (eds.) Jepson eFlora, /eflora/eflora_display.php?tid=3184, accessed on May 25, 2020.

Citation for the whole project: Jepson Flora Project (eds.) 2020, Jepson eFlora,, accessed on May 25, 2020.

Hazardia detonsa
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© 2014 Steve Matson
Hazardia detonsa
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© 2009 Gary A. Monroe
Hazardia detonsa
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© 2003 Keir Morse
Hazardia detonsa
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© 2003 Keir Morse
Hazardia detonsa
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© 2014 Steve Matson
Hazardia detonsa
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© 2010 Vernon Smith

More photos of Hazardia detonsa in CalPhotos

Geographic subdivisions for Hazardia detonsa:
n ChI.
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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 occurence).


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Data provided by the participants of the  Consortium of California Herbaria.
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All markers link to CCH specimen records. The original determination is shown in the popup window.
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.
Yellow markers indicate records that may provide evidence for eFlora range revision or may have georeferencing or identification issues.

CCH collections by month

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).