Lactuca serriola L.

Prickly lettuce

Some wild lettuce species

	Lactuca biennis	Lactuca canadensis	You are here Lactuca serriola
Common Name	tall blue lettuce	wild lettuce	prickly lettuce
Plant	Tall blue lettuce grows up to 6′ (1.8 m) high.	4–10′ (1.2–3 m) tall, with stems that are green or spotted with purple. The latex from a broken stem is brown.	Erect, 12–79″ (30–200 cm) tall. Stems sometimes have stiff hairs near the bottom; stems and leaves have a milky sap when cut.
Leaves	Leaves are deeply divided, like those of dandelions, but while dandelion leaves are roughly the same width along their length, these are more triangular in overall shape. They are up to 1′ (30 cm) long and 6″ (15 cm) wide at the base, tapering to sharp tips. Leaves are hairy, undersides more so.	Vary greatly in shape, and may resemble the shape of a sickle, or long and narrow, or wider and deep lobes. They are 6–14″ (15–35 cm) long.	Alternate, 1¾–12″ (5–30 cm) long and ⅜–4″ (1–10 cm) wide. The mid-ribs of leaves have prickers along the bottom. Typically leaves are deeply lobed.
Flowers	Blue, about ¼–½″ (6.3–12 mm) across, in crowded clusters at the top.	At the top, large cone-shaped panicles consisting of 50-100 flowers appear. Individual flowers are about ¼″ (8.5 mm) around, with 15-22 florets (tiny petals) each. They are yellow, pinkish-orange, or reddish.	In panicles that form open, roughly conical clusters of flowers. Flowers are ⅜–½″ (1–1.5 cm) in diameter, and have 13-27 florets (petals) each. Flowers appear July-September.
Fruit	Mottled achenes ⅛″ (5 mm) long.	Achenes (seeds) are small and brown, each with a "parachute" attached, like dandelions.	⅛″ (3 mm) long, single-seeded, lance-shaped, attached to a "parachute" like dandelions.
Range/ Zones
Habitats	Redwood forest, wetlands	Woodland margins, clearings, near the edges of water, roadsides, pastures.	Grasslands, seasonal wetlands, orchards, vineyards, urban places, roadsides, disturbed habitats.

	Mycelis muralis
Common Name	wall lettuce
Plant	10–59″ (25–150 cm) tall, with green or purplish hairless stems that exude a milky latex.
Leaves	Leaves are 1¾–9″ (5–22 cm) long. Lower leaves are lyre-shaped, heavily divided into irregularly shaped sections. Upper leaves are alternate, sessile and less heavily divided. All leaves are red tinged; leaf undersides are sometimes crimson-colored.
Flowers	Flowerheads are loose, highly branched, sparse-looking panicles. Flowers are yellow, and less than ⅜″ (1 cm) in diameter. Each flower is a technically a composite flower, lacking a central disc, with four to five ray florets. Petal tips may have teeth. Flowers are hermaphroditic, able to self-pollinate. Flowers appear from June to September.
Fruit	Achenes are ⅛″ (3.3 mm) long, flattened, and dark brown, with short yellow beaks. Each one has a white, delicate-looking pappus.
Range/ Zones
Habitats	Human disturbed habitats such as shaded woodlands, meadows, rock walls, and fields.

Lactuca serriola description by Thomas H. Kent, not updated.

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