Species: Lactuca ludoviciana (Nutt.) Riddell

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Lactuca ludoviciana (Nutt.) Riddell

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TAXONOMY

Family:

Asteraceae or Compositae

Genus:

Lactuca

Species Synonyms:

Lactuca campestris Greene
Lactuca campestris var. typica Wieg.

Common Names:

wild lettuce
biannual lettuce
western wild lettuce

DISTRIBUTION

Canada:

south eastern Saskatchewan – southern Manitoba

Saskatchewan:

southeastern Saskatchewan; Antler River Valley

Ecoregion:

Aspen Parkland

HABITAT

Saskatchewan:

low shrublands in river valleys

RARITY STATUS

Provincial Status According
to Harms (2003):

Endangered

Nature Conservancy Status:

G4G5 S1

Saskatchewan Species at
Risk Status:

None

COSEWIC Status:

None

Lactuca ludoviciana is endangered because it is extremely rare in the province and is restricted to one region.

SPECIES DESCRIPTION

Height:

1 – 2 m tall

Roots:

taproot

Stems:

to 1 cm wide, solid, glabrous, latex brown

Leaves:

basal and lower leaves sessile, 20 – 30 cm long, 5 – 10 cm wide, ovate to obovate, base sagittate to clasping, glabrous, adaxial midvein hirsute, variously dentate or pinnatifed; middle and upper leaves alternate, auriculate clasping, 5 – 15 cm long, 3 – 5 cm wide, reduced slightly upwards, ovate to obovate, dentate to pinnately lobed, margins sharp but not prickly

Inflorescence:

heads 50 – 100 in loose panicles, to 1 cm across, cylindrical, ligulate florets only; phyllaries ~17, 15 – 23 mm high, imbricate, not black-tipped

Flowers:

ligulate florets 20 – 30; 5 – 5.5 mm long, blue, blue with yellow at apex or yellow; anthers white

Fruits:

achenes 4 – 5 mm long, 2 – 3 mm wide, flattened, conspicuous ridge on both sides, dark brown; beak 3 – 4 mm long, filiform; pappus in 3 – 4 series, white

*KEY TO LACTUCA* IN SASKATCHEWAN**

1 Pappus brown or grey	L. biennis
1 Pappus white	2

2 Flowers yellow (may dry purple)	3
2 Flowers purple (may have some yellow)	4

3 Leaves prickly on margin; heads with 6 – 12 florets; latex white	L. serriola
3 Leaves not prickly on margin; heads with 12 – 20 florets; latex brown	L. ludoviciana

4 Leaves prickly on margin; latex white (flowers only purplish when dried)	L. serriola
4 Leaves not prickly on margin; latex white or brown	5

5 Plants not glaucous; achenes very flat, median nerve strong, other nerves if present, obscure, beak long and slender; latex brown	L. ludoviciana
5 Plants glaucous; achenes moderately compressed, several prominent nerves, beak short; latex white	L. tartarica var. pulchella