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Vascular Plants of California
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Tetradymia canescens

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: TetradymiaView DescriptionDichotomous Key

Habit: Shrub. Stem: +- tomentose. Leaf: alternate and generally clustered in axils, linear to (ob)lanceolate, sometimes persisting as stiff spines, glabrous to tomentose. Inflorescence: heads discoid, axillary or in +- rounded or flat-topped, terminal clusters; involucre cylindric to hemispheric; phyllaries 4--6 in 1--2 +- equal series, often keeled; receptacle flat, epaleate. Disk Flower: 4--9; corolla cream to yellow, lobes long, spreading or recurved; anther base +- sagittate, tip obtuse or acute; style branches papillate to short-bristly, tips truncate to conic. Fruit: obconic or fusiform, often 5-angled; pappus 0 or of generally many bristles or slender scales.
Species In Genus: 10 species: western North America. Etymology: (Greek: 4 together, from 4-flowered heads of some species) Toxicity: Esp flower buds TOXIC to sheep (toxicity poorly understood).
eFlora Treatment Author: David J. Keil
Reference: Strother 2006 FNANM 20:629--632
Unabridged Reference: Strother 1974 Brittonia 26:177--202
Tetradymia canescens DC.
Habit: Plant 1--8 dm, unarmed. Stem: unevenly tomentose, becoming +- glabrous in stripes below nodes. Leaf: main leaves <= 4 cm, +- (ob)lanceolate, tomentose to silvery; clustered leaves like (generally <) main leaves. Inflorescence: heads generally 3--6(10) in flat-topped clusters; peduncle 5--15(25) mm, bracts 0; involucre 6--8(12) mm, cylindric to obconic; phyllaries 4, oblong to ovate. Flower: 4; corolla 7--15 mm, creamy to bright yellow. Fruit: 2.5--5 mm, glabrous or short-stiff-hairy; pappus of many fine bristles, 6--11 mm. Chromosomes: 2n=60,62,90,120.
Ecology: Sagebrush scrub, pinyon/juniper woodland, conifer forest; Elevation: (700)1000--3400 m. Bioregional Distribution: CaRH, SNH, TR, s PR, GB, DMoj; Distribution Outside California: to British Columbia, Montana, Wyoming, New Mexico. Flowering Time: Jul--Oct
Jepson eFlora Author: David J. Keil
Reference: Strother 2006 FNANM 20:629--632
Unabridged Reference: Strother 1974 Brittonia 26:177--202
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Botanical illustration including Tetradymia canescens

botanical illustration including Tetradymia canescens


Citation for this treatment: David J. Keil 2012, Tetradymia canescens, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on December 17, 2018.

Citation for the whole project: Jepson Flora Project (eds.) 2018, Jepson eFlora,, accessed on December 17, 2018.

Tetradymia canescens
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© 2012 Steve Matson
Tetradymia canescens
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© 2008 Vernon Smith
Tetradymia canescens
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© 2015 Aaron Schusteff
Tetradymia canescens
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© 2006 Steve Matson
Tetradymia canescens
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© 2007 Steve Matson
Tetradymia canescens
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© 2015 Steve Matson

More photos of Tetradymia canescens in CalPhotos

Geographic subdivisions for Tetradymia canescens:
CaRH, SNH, TR, s PR, GB, DMoj;
Markers link to CCH specimen records. Yellow markers indicate records that may provide evidence for eFlora range revision or may have georeferencing or identification issues. Purple markers indicate specimens collected from a garden, greenhouse, or other non-wild location.
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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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.