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annual sow-thistle, common sow-thistle, laiteron, sow thistle

Habit Annuals or biennials, 10–140(–200) cm.

bases soft to hard, herbaceous, often hollow.


blades of mid cauline spatulate or oblong to obovate or lanceolate, 6–35 × 1–15 cm, bases auriculate, auricles deltate to lanceolate, ± straight, acute, margins usually pinnately (often runcinately) lobed, lobes ± deltate to lanceolate, not constricted at bases, terminals usually larger than laterals, entire or dentate.


usually glabrous, sometimes stipitate-glandular.


9–13+ mm.


ligules ± equaling tubes.


usually glabrous, sometimes tomentose and/or stipitate-glandular.


dark brown, mostly oblanceoloid, 2.5–3.5+ mm, ribs 2–4 on each face, faces transversely rugulose or tuberculate across and between ribs;

pappi 5–8 mm.


= 32, 36.

Sonchus oleraceus

Phenology Flowering (Apr–)Jul–Oct (year-round in south).
Habitat Disturbed sites, gardens, roadsides, along streams
Elevation 0–2000 m (0–6600 ft)
from FNA
AK; AL; AR; AZ; CA; CO; CT; DC; DE; FL; GA; IA; ID; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; MT; ND; NE; NH; NJ; NM; NV; NY; OH; OK; OR; PA; RI; SC; SD; TN; TX; UT; VA; VT; WA; WI; WV; WY; AB; BC; MB; NB; NF; NS; NT; ON; PE; QC; SK; SPM; Greenland; Europe [Introduced in North America; introduced also in Mexico, West Indies, Bahamas, Central America, South America, Africa, Asia, Pacific Islands (New Zealand), Australia]
[WildflowerSearch map]
[BONAP county map]
Source FNA vol. 19, p. 275.
Parent taxa Asteraceae > tribe Cichorieae > Sonchus
Sibling taxa
S. arvensis, S. asper, S. palustris, S. tenerrimus
Name authority Linnaeus: Sp. Pl. 2: 794. (1753)
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