Lactuca serriola |
Lactuca ludoviciana |
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prickly lettuce |
biannual lettuce, Louisiana lettuce, Louisiana wild lettuce, prairie lettuce, western lettuce |
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Habit | Annuals (perhaps persisting), (15–)30–70(–100+) cm. | Biennials, 15–150 cm. |
Leaves | on proximal 1/2–3/4 of each stem; blades of undivided cauline leaves usually ± oblong, sometimes obovate to lanceolate, margins denticulate, usually prickly, midribs usually prickly-setose, rarely smooth. |
on proximal 1/2–3/4 of each stem; blades of undivided cauline leaves obovate or oblanceolate to spatulate, margins denticulate (piloso-ciliate), midribs usually piloso-setose. |
Involucres | 9–10(–12) mm. |
12–15+ mm. |
Florets | 12–20; corollas yellow, usually deliquescent. |
20–50+; corollas usually yellow, sometimes bluish, usually deliquescent. |
Phyllaries | usually reflexed in fruit. |
usually reflexed in fruit. |
Heads | in paniculiform arrays. |
in paniculiform arrays. |
Cypselae | bodies pale grayish to tan, ± flattened, oblanceolate, 2.5–3.5 mm, beaks ± filiform, 2.5–4 mm, faces (3–)5–9-nerved; pappi white, (3–)4–5 mm. |
bodies brown to blackish (usually mottled), ± flattened, elliptic, 4.5–5+ mm, beaks ± filiform, 2.5–4.5 mm, faces 1(–3)-nerved; pappi white, 5–7(–11) mm. |
2n | = 18. |
= 34. |
Lactuca serriola |
Lactuca ludoviciana |
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Phenology | Flowering (May–)Jul–Sep(–Oct). | Flowering Jun–Sep. |
Habitat | Roadsides, disturbed sites | Openings in woods, stream banks, prairies |
Elevation | 10–2300 m (0–7500 ft) | 100–1400 m (300–4600 ft) |
Distribution |
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; NC; 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; NS; ON; PE; QC; SK; Europe [Introduced in North America; also introduced nearly worldwide]
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AR; AZ; CA; CO; IA; ID; IL; IN; KS; KY; LA; MN; MT; ND; NE; NM; OK; OR; SD; TX; UT; WA; WI; WY; BC; MB; SK
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Discussion | The name Lactuca scariola Linnaeus is evidently illegitimate; it is a superfluous name based on the same type as L. serriola. Plants included here in L. serriola with most leaf blades obovate to lanceolate (not lobed) and lacking prickles on midribs have been called L. scariola subsp. or var. integrata or L. serriola forma integrifolia or L. serriola var. integrata. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 19, p. 262. | FNA vol. 19, p. 262. |
Parent taxa | Asteraceae > tribe Cichorieae > Lactuca | Asteraceae > tribe Cichorieae > Lactuca |
Sibling taxa | ||
Synonyms | Sonchus ludovicianus, L. campestris | |
Name authority | Linnaeus: Cent. Pl. II, 29. (1756) | (Nuttall) Riddell: W. J. Med. Phys. Sci. 8: 491. (1835) |
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