Daisy family (Asteraceae) ⁶

Summary ⁷

Lactuca serriola, also called prickly lettuce, milk thistle (not to be confused with Silybum marianum, also called milk thistle) compass plant, and scarole, is an annual or biennial plant in the dandelion tribe within the daisy family. It has a slightly fetid odor and is commonly considered a weed of orchards, roadsides and field crops. It is the closest wild relative of cultivated lettuce (Lactuca sativa L.).

Recognition ⁶

•Row of prickles beneath leaf midrib
•Leaf with angular lobes
•Milky sap
•Small yellow flowers producing dandelion-like seed heads

Similar species ⁶

Sowthistles (Sonchus oleraceus and Sonchus arvensis are similar, but lack prickles below the leaf midrib. Other wild lettuce species, such as Lactuca canadensis, also lack these prickles.

Learn more ⁶

Midwest Invasive Species Information Network.

Sources and Credits

1. (c) Leonard Rüdenberg, some rights reserved (CC BY), uploaded by Leonard Rüdenberg, https://www.inaturalist.org/observations/57310365
2. (c) Дарья Друщенко, some rights reserved (CC BY), uploaded by Дарья Друщенко, https://www.inaturalist.org/observations/55781588
3. (c) Sandy Wolkenberg, some rights reserved (CC BY), uploaded by Sandy Wolkenberg, https://www.inaturalist.org/observations/131520989
4. (c) Gilles Ayotte, some rights reserved (CC BY), uploaded by Gilles Ayotte, https://commons.wikimedia.org/wiki/File:Lactuca_serriola_15-p.bot-lactu.scari-03.jpg
5. (c) sarahnwilson, some rights reserved (CC BY), uploaded by sarahnwilson, https://www.inaturalist.org/observations/14211403
6. (c) Isaac Winkler, some rights reserved (CC BY-SA)
7. Adapted by Isaac Winkler from a work by (c) Wikipedia, some rights reserved (CC BY-SA), https://en.wikipedia.org/wiki/Lactuca_serriola

More Info

• iNat taxon page
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