Prickly Lettuce Plant (IMAGE) Washington State University Caption Prickly lettuce, the wild relative of cultivated lettuce, is a potential source for the production of natural rubber. Credit Jim Kennedy (<a target="_blank"href="https://creativecommons.org/licenses/by/2.0/">CC BY 2.0</a>, Flickr) Usage Restrictions <a target="_blank"href="https://creativecommons.org/licenses/by/2.0/">CC license</a> requires linking <a target="_blank"href="https://www.flickr.com/photos/nature80020/14468612435/in/photolist-2Zdpoq-68jMci-o3xqp6-6eRVLg-5bSqXC-5bSr4U-68oZxo-68jMkk-68jLX8-68oZiG-68oZHY-oi3de2-o1yNTX-8zgQJr-8zjY6y-o1xyB5-o1xyBW-ohKArZ-ohKAFr-8zjXmS-8zgPpK-8zjXhf-8zjXsJ-8zjXCy-8zgQ9x-8zjYXy-8zgNu2-8zgNoT-8zjYm7-8zgQn6-8zjWJ9-8zgNG8-8zgNfg-8zjX1Q-rp3C8L-oaktuX-gDnB8r-6M8kEL-gDnwPh/">here</a> License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.