Lactuca serriola |
Lactuca sativa |
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prickly lettuce |
cultivated lettuce, garden lettuce |
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Habit | Annuals (perhaps persisting), (15–)30–70(–100+) cm. | Annuals or biennials, (15–)30–70(–100+) 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 ovate to orbiculate, margins entire or denticulate, seldom prickly, midribs rarely prickly-setose. |
Involucres | 9–10(–12) mm. |
8–13+ mm. |
Florets | 12–20; corollas yellow, usually deliquescent. |
7–15(–30+); corollas yellow (sometimes streaked with violet), usually deliquescent. |
Phyllaries | usually reflexed in fruit. |
usually erect in fruit. |
Heads | in paniculiform arrays. |
usually in corymbiform, sometimes 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 pale grayish to whitish or tan, ± flattened, obovate, 3–4 mm, beaks ± filiform, 3–5 mm, faces 5–9-nerved; pappi white, 3.5–4+ mm. |
2n | = 18. |
= 18. |
Lactuca serriola |
Lactuca sativa |
|
Phenology | Flowering (May–)Jul–Sep(–Oct). | Flowering mostly Jul–Sep. |
Habitat | Roadsides, disturbed sites | Disturbed sites, abandoned plantings |
Elevation | 10–2300 m (0–7500 ft) | 10–1000 m (0–3300 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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AL; CA; CT; DC; DE; ID; IL; IN; MA; ME; MI; MO; NC; ND; NH; NJ; NM; NY; OH; OK; OR; PA; RI; VT; WA; WV; ON; Eurasia [Introduced in North America; introduced also in Mexico; introduced or ephemeral nearly worldwide]
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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. 263. |
Parent taxa | Asteraceae > tribe Cichorieae > Lactuca | Asteraceae > tribe Cichorieae > Lactuca |
Sibling taxa | ||
Name authority | Linnaeus: Cent. Pl. II, 29. (1756) | Linnaeus: Sp. Pl. 2: 795. (1753) |
Web links |
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