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prickly lettuce

biannual lettuce, Louisiana lettuce, Louisiana wild lettuce, prairie lettuce, western lettuce

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

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
from FNA
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]
[WildflowerSearch map]
[BONAP county map]
from FNA
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
[WildflowerSearch map]
[BONAP county map]
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.)

Source FNA vol. 19, p. 262. FNA vol. 19, p. 262.
Parent taxa Asteraceae > tribe Cichorieae > Lactuca Asteraceae > tribe Cichorieae > Lactuca
Sibling taxa
L. biennis, L. canadensis, L. floridana, L. graminifolia, L. hirsuta, L. ludoviciana, L. saligna, L. sativa, L. virosa
L. biennis, L. canadensis, L. floridana, L. graminifolia, L. hirsuta, L. saligna, L. sativa, L. serriola, L. virosa
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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