Lactuca canadensis

Native

Moderate moisture. Fields, meadows, thickets, woods, waste places.

July to September

Pale yellow

1′ to 8′

This is a 1′ to 8′ tall, erect. biennial forb with a thick, deep taproot. The stems and leaves contain a milky latex.

The stems are leafy, smooth, light green, and may have purple streaks.

The leaves are alternate, light gray-green to dark green, often with purple edges or a yellowish cast. They are up to 10″ long and 3″ wide. They are stemless, with the basal lobes partly surrounding the stem (clasping). They do not have prickles on the leaf margin. The midvein on the underside may have short, fine hairs, but not prickles.

The inflorescence is a tall, narrow, cone-shaped, loosely-branched cluster.

The flower heads are about ⅜″ across and have 13 to 22 ray florets.

The fruit is a brown achene with fluffy, white bristles attached to the tip.

Prickly lettuce (Lactuca serriola) has blue-green leaves with prickles on the leaf margins and on the underside of the midvein. The pale yellow rays in the flower heads have truncated tips with 5 small teeth.

The blue species of Lactuca (below) are extremely variable and identifying characteristics overlap, factors which, taken together, make the species difficult to separate.

Showy blue lettuce (Lactuca tatarica ssp. pulchella) has large, showy flower heads that measure, ¾″ across.

Tall blue lettuce (Lactuca biennis) has bluish to white flowers. The achene has grayish-brown bristles attached to the tip.

Woodland lettuce (Lactuca floridana var. floridana) has light blue flowers.