Canada lettuce
Family
AsteraceaeScientific Name
Lactuca canadensis
Synonyms (former Scientific Names):
Lactuca canadensis var. typica
Lactuca canadensis var. longifolia
Lactuca canadensis var. obovata
Lactuca steelei
Lactuca canadensis var. latifolia
Lactuca canadensis var. integrifolia
Lactuca sagittifolia
Habit
Canada lettuce is non-woody and grows upright from 3-8ft tall. It typically does not have branches but a hairless green (sometimes red) main stem.
Leaves
Its leaves are light/dark green; some purple can be seen on the edges and arranged alternately. The leaves can be 10 inches (250mm) long and 3 inches wide (75mm). They are oblong/lanceolate. Most leaves have lobes; the largest leaves have large lobes, while the smaller leaves have smaller lobes. The leaves may have hairs along the bottom of the vein.
Identifying Characteristics
Latuca canadensis is similar to prickly lettuce (Lactuca serriola); however, Canada is more green, while prickly has a blue tint. Canada lettuce also has achenes that are longer than the thread-beaks.
Flower Seed Head
The flowers are typically yellow/reddish-orange and 8-25mm in diameter. The flowers typically bloom in late summer/fall.
Seed Fruit
The seeds are achenes (small, one-seeded dry fruit, that don't split) with white hair and black spots. They are attached by beaks (thread-like).
Where Found
Can be found in woods, pastures, roadsides, gravel lots, landscape beds, and crop fields.
Growth Habit
upright and nonwoody
Thorns or Spines
not present
Approximate Flower Diameter
Varies:
pencil,
dime,
nickle,
quarter
Dominant Flower Color
Varies:
yellow,
red,
orange
Flower Symmetry
radial symmetery
Leaf Hairs
Varies:
has hairs,
no hairs
Leaf Shape
Varies:
lance,
oval
Leaf Arrangement
alternate
Leaf Margin
Varies:
lobed,
serrated
Leaf Structure
simple
Leaf Stalk
none
Stem Hairs
no hairs
Stem Cross Section
round or oval
Milky Sap
present
Root Structure
taproot
Life Cycle
biennial
Ochrea
not present
Plant Type
Herb