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cultivated lettuce, garden lettuce

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

Habit Annuals or biennials, (15–)30–70(–100+) cm. Biennials, 15–150 cm.
Leaves

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.

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

8–13+ mm.

12–15+ mm.

Florets

7–15(–30+);

corollas yellow (sometimes streaked with violet), usually deliquescent.

20–50+;

corollas usually yellow, sometimes bluish, usually deliquescent.

Phyllaries

usually erect in fruit.

usually reflexed in fruit.

Heads

usually in corymbiform, sometimes in paniculiform, arrays.

in paniculiform arrays.

Cypselae

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.

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 sativa

Lactuca ludoviciana

Phenology Flowering mostly Jul–Sep. Flowering Jun–Sep.
Habitat Disturbed sites, abandoned plantings Openings in woods, stream banks, prairies
Elevation 10–1000 m (0–3300 ft) 100–1400 m (300–4600 ft)
Distribution
from FNA
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]
[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]
Source FNA vol. 19, p. 263. 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. serriola, 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: Sp. Pl. 2: 795. (1753) (Nuttall) Riddell: W. J. Med. Phys. Sci. 8: 491. (1835)
Web links