Lactuca in Manitoba - more puzzles :)

Lactuca

Native

Lactuca biennis (Moench) Fernald - Tall Blue Lettuce

• (BC AB SK MB ON QC NB PE NS NL-N NL-L) Vascan
• blue flowers, leaves irregularly pinnatifid, ; pappus brown, achenes nearly beakless²
• biennial²
• swampy or moist places; boreal forest ¹

Lactuca canadensis Linnaeus - Canada Wild Lettuce

• (MB ON QC NB PE NS) Vascan
• yellow flowers
• rare, boreal forest ¹

Lactuca floridana (Linnaeus) Gaertner - Woodland Lettuce

• (MB ON) Vascan
• blue flowers
• leaves petiolate, toothed and often also pinnatifid, pubescent on the underside of the main veins; pappus white ¹
• margins of woods, boreal forest¹
• rarely observed

Lactuca ludoviciana (Nuttall) Riddell - Western Lettuce

• (SK MB) Vascan
• yellow or blue flowers, leaves mostly pinnatifid, spinulose margined and more or less prickly on the mid-rib beneath and strongly glaucous, pappus white, achenes distinct soft filiform beak, ²
• along riverbanks, parklands¹
• rarely observed

introduced

Lactuca serriola Linnaeus - Prickly Lettuce

• Vascan
• yellow flowers
• leaves copiously spinulose-denticulate, spinulose bristly on mid rib underneath and tending to turn with one edge up²
• very common; roadsides, slough margins, waste places, cultivated land; throughout Prairie provinces¹
• previously known as Lactuca scariola

Mulgedium

Native

Mulgedium pulchellum (Pursh) G. Don - Blue Lettuce

• (BC AB SK MB ON QC) Vascan
• blue flowers
• leaves entire, lower leaves may be more or less lobed; pappus white, achenes with short firm beak²
• perennial²
• common...cultivated lands and roadsides, throughout Prairie provinces¹
• previously known as Lactuca pulchella or Lactuca tatarica var pulchella

What I am going to try out

looks like habitat, flower color / number and leaves are the most helpful things - with a nod to the color of the pappus - that is the fluffy stuff attached to the seed to help it drift on the wind.

the prickly ones...

• if the plant is in proximity to human disturbance and the flower is yellow and the leaves are turned to be perpendicular to the ground- edge to the sky >>> Lactuca serriola
• if the plant is along a river (or other damp to wet ground) and the flowers are yellow or blue >>> Lactuca ludoviciana (L ludoviciana tends to have more flowerheads (12-20) over L serriola (5-12))

the non-prickly ones....

• if the flowers are blue and the pappus is white and the upper leaves are entire and the plant is commonly seen >>> Mulgedium pulchellum / Lactuca pulchella (two names for the same plant)
• if the flowers are blue and the pappus is brown and the leaves are pinnatifid and the plant is in a wet spot in the boreal>>> Lactuca biennis (especially if the plant is 2 meters or taller)
• if the flowers are blue and the pappus is white and the leaves are pinnatifid and the plant is at a forest edge in the boreal>>> Lactuca floridana
• if the flowers are yellow >>>Lactuca canadensis

References

1. Budd, A.C.; Looman, J., Best, K.F., Budd's Flora of the Canadian Prairie Provinces, 1979 Ottawa
2. Scoggan, H.J, Flora of Manitoba, 1957 Ottawa

Publicado el 16 de agosto de 2021 por marykrieger