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Sonchus oleraceus
COMMON SOW THISTLE

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: SonchusView DescriptionDichotomous Key

Common Name: SOW THISTLE
Habit: Annual to perennial herb [shrub]; sap milky. Stem: erect, smooth, distally branched. Leaf: basal and cauline, alternate, +- entire to toothed and coarsely pinnate-lobed; cauline generally sessile, clasping. Inflorescence: heads liguliflorous, in cyme-like clusters; involucre swollen at base; phyllaries generally in 3 series, outer many, short-triangular, inner series linear, tapered; receptacle +- flat, epaleate. Flower: many; ligule yellow, readily withering. Fruit: generally +- flat, beakless; pappus of many fine, white bristles.
Species In Genus: +- 55 species: Eurasia, Africa. Etymology: (Ancient Greek name for a kind of thistle)
eFlora Treatment Author: David J. Keil & G. Ledyard Stebbins

Sonchus oleraceus L.
NATURALIZED
Habit: Annual 1--14 dm. Stem: often proximally branched. Leaf: basal generally < cauline, generally tapered or abruptly wing-petioled; cauline 5--35 cm, distal often widest at base, proximal clasping lobes acute, not curled or coiled; blades nearly all lobed except in dwarfed pls, lobes variable in width, terminal lobe often widely arrowhead-shaped. Inflorescence: peduncle 0.5--7 cm, glabrous to bristly-glandular, sometimes cottony-tomentose just proximal to heads; involucre 10--13 mm. Flower: ligule +- = tube. Fruit: 2.5--3.8 mm, flat, 2--4-ribbed, cross-wrinkled, dark brown; pappus bristles +- 2 × fruit. Chromosomes: 2n=32.
Ecology: Abundant. Disturbed places; Elevation: < 2500 m. Bioregional Distribution: CA; Distribution Outside California: North America; native to Europe. Flowering Time: All year Note: Much like Sonchus asper.
eFlora Treatment Author: David J. Keil & G. Ledyard Stebbins
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Citation for this treatment: David J. Keil & G. Ledyard Stebbins 2016. Sonchus oleraceus, in Jepson Flora Project (eds.) Jepson eFlora, http://ucjeps.berkeley.edu/cgi-bin/get_IJM.pl?tid=5118, accessed on December 03, 2016.

Citation for the whole project: Jepson Flora Project (eds.) 2016. Jepson eFlora, http://ucjeps.berkeley.edu/IJM.html, accessed on December 03, 2016.


Sonchus oleraceus
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© 2015 Keir Morse
Sonchus oleraceus
click for enlargement
© 2015 Keir Morse
Sonchus oleraceus
click for enlargement
© 2012 Neal Kramer
Sonchus oleraceus
click for enlargement
© 2015 Keir Morse
Sonchus oleraceus
click for enlargement
© 2015 Keir Morse
Sonchus oleraceus
click for enlargement
© 2012 Neal Kramer

More photos of Sonchus oleraceus in CalPhotos


Geographic subdivisions for Sonchus oleraceus:
CA;
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.
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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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CCH collections by month

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