prickly sowthistle (Sonchus asper) — identification, habitat & look-alikes

Prickly sowthistle is a widespread introduced weed in the United States, with glossy leaves edged by firm prickles. Its yellow flower heads mature into white, fluffy seed heads that are easily carried by wind.

Appearance

Growth form: It is an or with a hollow stem that releases milky sap when cut.
Leaves: The dark green leaves are glossy and sharply prickly along the edges. Rounded, ear-like lobes at the leaf base clasp the stem.
Flowers: Yellow, strap-shaped flowers cluster into heads that resemble small dandelion flowers.
Fruit: Each dry, flattened fruit carries one seed and a tuft of white hairs.

Look-alikes

annual sowthistleSonchus oleraceus

Prickly sowthistle has darker, glossier leaves with firmer prickles and rounded lobes that clasp the stem. Annual sowthistle (Sonchus oleraceus) usually has softer leaves and more pointed clasping lobes.

Why they get mixed upBoth have milky sap, yellow flower heads, and fluffy white seed heads.

Where it lives

Typical habitats: roadsides
farm fields
gardens
waste ground
Range: It is native to Europe, North Africa, and nearby parts of western Asia, and it has been introduced across much of the United States.
Preferred conditions: It favors sunny, disturbed places with fertile soil and some moisture.

Life cycle

Reproduction: The plant reproduces by seed.
Seed dispersal: The white hairs help the seeds travel on the wind.

Conservation

IUCN Red List: NENot EvaluatedNot yet assessed

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