Datura innoxia, a member of the nightshade family, is known by several common names, including pricklyburr, moonflower, and toloache. This plant is recognized for its ornamental value while also being understood as highly toxic. It produces large, fragrant, trumpet-shaped white flowers that bloom at night. This contrast between its aesthetic appeal and its inherent toxicity makes it a subject of both admiration and caution.
Identification and Habitat
Datura innoxia is a sprawling herbaceous plant that can grow up to 1.5 meters tall. Its stems and leaves are covered in fine, soft grayish hairs, which give the plant a downy, gray-green appearance and a soft texture. The leaves are broad, have smooth edges, and are arranged alternately along the stems. A primary identifying feature is its large, white, trumpet-shaped flowers, measuring between 12 and 19 centimeters long, which open in the evening and wilt by the following day.
The plant’s fruit is another defining characteristic, giving it the common name pricklyburr. It is a spiky, egg-shaped capsule about 5 centimeters in diameter that hangs downwards on a curved stalk. This capsule is covered with numerous slender, needle-like spines. It begins as green and dries to a brown color, eventually splitting open to disperse its many small, brown seeds.
Native to the Southwestern United States, Mexico, and Central America, D. innoxia thrives in arid environments and is frequently found in disturbed soils, such as along roadsides, in uncultivated fields, and in overgrazed pastures. Its tolerance for dry conditions has allowed it to become naturalized in temperate and tropical regions across the globe. The plant spreads through both seeds and vegetative cuttings.
Chemical Composition and Toxicity
All parts of the Datura innoxia plant are poisonous due to the presence of potent tropane alkaloids. The primary compounds responsible for its toxicity are scopolamine, atropine, and hyoscyamine. These substances are anticholinergics, meaning they work by blocking the neurotransmitter acetylcholine in the central and peripheral nervous systems. This disruption leads to severe physiological and psychological effects. The concentration of these alkaloids can vary significantly based on age, growing conditions, and different parts of the same plant, making any ingestion hazardous.
Symptoms of Datura poisoning begin within 30 to 60 minutes after ingestion. Initial effects include severe thirst, dry mucous membranes, blurred vision, and sensitivity to light due to dilated pupils. As the toxicity progresses, victims may experience a rapid heartbeat, elevated body temperature, and decreased gut motility. Central nervous system effects lead to confusion, agitation, delirium, and hallucinations that make it impossible to distinguish reality from fantasy.
The state of intoxication can last from 24 hours to several days, with some reports of symptoms persisting for up to two weeks. In severe cases, poisoning can result in seizures, respiratory depression, coma, and death. Due to the unpredictable potency and the narrow margin between a psychoactive dose and a lethal one, there is no safe way to use Datura innoxia. Any form of consumption is strongly warned against.
Historical and Cultural Significance
The ethnobotanical history of Datura innoxia is rooted in the spiritual practices of various indigenous peoples of the Americas. Groups such as the Chumash and Zuni have historically used the plant as a sacred entheogen. It was central to spiritual ceremonies, rites of passage, and acts of divination, where its psychoactive properties were believed to facilitate contact with the supernatural world. For the Chumash, Datura was used to gain insight, cure serious illnesses, and counteract negative omens.
Use of the plant was highly ritualized and controlled, administered by trained specialists or shamans who possessed detailed knowledge of its preparation and risks. These individuals understood how to navigate its effects to seek visions or diagnose ailments. The plant was also employed in traditional medicine for its anesthetic and pain-relieving properties, particularly for treating wounds or setting bones.
This historical usage highlights the reverence and caution with which the plant was handled. It was not used casually but as a tool for specific, culturally significant purposes. The knowledge required to use it was passed down through generations, emphasizing the respect it commanded.
Distinguishing From Similar Plants
Datura innoxia can be differentiated from Datura stramonium (Jimsonweed) by its foliage and fruit. D. innoxia has soft, hairy leaves giving it a downy appearance, and its fruit is covered in a dense layer of many fine, needle-like spines. In contrast, D. stramonium has smooth, hairless leaves and its fruit features fewer, but much larger and thicker, spines. The flower of D. innoxia is also larger with ten points, while the flower of D. stramonium is smaller with five points.
Another point of confusion can arise between the Datura genus and the closely related Brugmansia genus, both called “Angel’s Trumpet.” The clearest distinguishing feature is the orientation of their flowers. Datura flowers are erect, pointing upwards. Conversely, Brugmansia flowers are pendulous, drooping downwards. Datura species are typically herbaceous annuals or short-lived perennials, whereas Brugmansia are woody shrubs or small trees.