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Lactuca serriola

Lactuca serriola

Lactuca serriola

Lactuca serriola (Prickly Lettuce)
Asteraceae (Sunflower Family)

Semi-desert, foothills, montane. Openings, disturbed areas, meadows, woodlands. Summer, fall.
Above and left: Hawkins Preserve, Cortez, September 2, 2016 and near Yellow Jacket Canyon, September 5, 2016.

Lactuca serriola is a biennial or winter annual that is a widespread, invasive species often filling fields and untended city lots. It grows with a strong, central, creamy-white stem; rather short, widely spaced side stems; large, prickly leaves; and many small, bright, yellow flower heads. The plant commonly grows to three feet tall, but it is not unusual for the plant to tower to five and six feet tall.

Linnaeus named the Lactuca genus and this species in 1756 from specimens collected in southern Europe. Latin gives us "lac" for "milk", alluding to the milky sap of this plant. Latin also gives us the specific epithet which may come from "seris", an ancient plant name for Chicory and "ola" a diminutive, thus "a little bit like Chicory", or "serriola" may allude to the saw-like, serrated leaf margins.

Lactuca serriola

Lactuca serriola (Prickly Lettuce)
Asteraceae (Sunflower Family)

Semi-desert, foothills, montane. Openings, disturbed areas, meadows, woodlands. Summer, fall.
Hawkins Preserve, Cortez, September 2, 2016.

Flower heads consist of about 6 to 20 ray flowers.

Lactuca serriola

Lactuca serriola

Lactuca serriola

Lactuca serriola

 

 

 

Lactuca serriola (Prickly Lettuce)
Asteraceae (Sunflower Family)

Semi-desert, foothills, montane. Openings, disturbed areas, meadows, woodlands. Summer, fall.
Near Yellow Jacket Canyon, September 5, 2016 and Hawkins Preserve, Cortez, September 2, 2016.

 

 

Seed heads are enclosed in the phyllaries after flowers fade.

 

 

 

 

 

 

 

 

Phyllaries dry, open, and reflex exposing the dark seeds with pappus hairs floating above them.

 

                                    Lactuca serriola

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Plumes of pappus hairs spread, eventually forming an exotic-looking sphere.

                          

Lactuca serriola

Lactuca serriola

Lactuca serriola

 

 

 

 

 

 

Lactuca serriola (Prickly Lettuce)
Asteraceae (Sunflower Family)

Semi-desert, foothills, montane. Openings, disturbed areas, meadows, woodlands. Summer, fall.
Hawkins Preserve, Cortez, September 2, 2016.

 

 

Lower leaves present a mesmerizing jumble of shapes and planes. Leaves are far more numerous and much larger in the first foot or so of the plant.

 

 

 

 

 

 

 

 

 

Leaves clasp the stem and commonly are auriculate (they have long, ear-like lobes). Because the lobes are offset they cause the leaf to twist and stand erect  --  but not all leaves are erect, as the horizontal leaf in the last photograph illustrates.

Leaf margins are entire to pinnately lobed and leaf edges are prickly and saw-toothed.

Range map © John Kartesz,
Floristic Synthesis of North America

State Color Key

Species present in state and native
Species present in state and exotic
Species not present in state

County Color Key

Species present and not rare
Species present and rare
Species extirpated (historic)
Species extinct
Species noxious
Species exotic and present
Native species, but adventive in state
Eradicated
Questionable presence

Lactuca serriola

Range map for Lactuca serriola