Lactuca virosa
Lactuca ludoviciana
bitter lettuce, great lettuce, poison wild lettuce, tall lettuce, wild lettuce
biannual lettuce, Louisiana lettuce, Louisiana wild lettuce, prairie lettuce, western lettuce
on proximal 1/2–2/3 of each stem;
blades of undivided cauline leaves obovate to spatulate, margins denticulate, midribs usually 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.
12–15 mm.
12–15+ mm.
10–15;
corollas yellow, usually deliquescent.
20–50+;
corollas usually yellow, sometimes bluish, usually deliquescent.
usually reflexed in fruit.
usually reflexed in fruit.
in paniculiform arrays.
in paniculiform arrays.
bodies purplish to blackish, ± flattened, ± elliptic, 3.5–4 mm, beaks ± filiform, 2.5–3.5 mm, faces 5–7-nerved;
pappi white, 5–6 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.
= 18.
= 34.
Lactuca virosa
Lactuca ludoviciana
- Local floras:
BC, 
CA, 
OR, 
WA - Local Web sites: CalFlora, CalPhotos,
Flora NW, 
IL Wildflowers, 
KS Wildflowers, 
LA Plants, 
MN Wildflowers, 
PNW Herbaria 
WildflowerSearch
iNaturalist (observations)
USDA Plants Database- LBJ Wildflower Center
- SEINet
- Plants of the World Online
- Encyclopedia of Life
- Wikipedia
- Google Image Search
