Rock art suggests that indigenous Californians consumed psychoactive plants

According to a study published online in the journal Proceedings of the National Academy of Sciences, a spiral symbol painted on the walls of a cave in Southern California depicts the flower of a native plant with hallucinogenic effects, the first clear evidence of ingesting psychoactive plants at a rock art site.

Datura wrightii, commonly known as Sacred Datura, is a species of poisonous perennial and ornamental flower of the Solanaceae family native to southwestern North America. D. Wrightii it blooms from April to October. The flowers are the most striking feature, being sweetly scented white trumpets up to 7.9 inches (20 cm) long, sometimes tinged with purple, especially at the margin. In clear weather, the flowers open in the morning and evening, but close at night and in cloudy weather, forming a spiral with five arms.

All parts of Datura plants contain dangerous levels of alkaloids, and ingesting low-concentrated plant extracts can cause seizures and hallucinations. An overdose can quickly provoke a state of panic, respiratory and heart failure.

Due to its psychoactive effects, Datura wrightii it is sacred to some Native Americans and has been used in ceremonies and rites of passage by Chumash, Tongva and others.

According to the study, a 400-year-old symbol painted on the Pinwheel Cave ceiling likely shows a stylized flower by Datura wrightii. Like members of the Solanaceae plant family, characterized by flowers with five petals arranged tightly around the bottom of the flower, the spiral depicted shows a 5-fold symmetry. Like the closed flower of Datura, the five arms of the spiral wrap around its central axis. Datura is also native to this part of Southern California and the plant can be found near the cave site.

Direct evidence of Datura’s consumption can be found on the cave walls. Small clumps of organic matter with high levels of mind-altering alkaloids scopolamine and atropine were found stuck on the rocks. Probably the dry remains of a ritual that involved the consumption of a mixture of plant leaves, lime powder and human saliva by the participants inside the cave.

According to radiocarbon dating of the organic remains found in the cave, such as lumps, seeds, and animal remains, people have repeatedly visited the cave from around 1600 to the late 1800s.