Lantana Camara L.—Lantana; yellow sage; red sage
FAMILY: Verbenaceae—the Vervain Family
This family is widespread in the tropics but sparingly represented in cool regions. None of the twelve or more species of Verbena occurring in Pennsylvania are toxic. The plant in this family that can be a problem is Lantana Camara, a common florist's subject, propagated in greenhouses and hanging-baskets. In Florida it is one of the most common causes of poisonings. Because no other members of the Verbenaceae are toxic, a family description is replaced by the plant characteristics listed below.
PHENOLOGY: Lantana is propagated by softwood cuttings and seeds. In our area it is a hot-house plant that is flowering when purchased, usually during spring and summer months.
DISTRIBUTION: Lantana Camara is found in homes, shopping malls, and greenhouses. It is most frequently sold in hanging-baskets.
PLANT CHARACTERISTICS: As a potted plant lantana becomes bushy and produces abundant flowers; stems: square; leaves: opposite, ovate, crenate-dentate, to 25 cm long, rough above, aromatic when crushed; inflorescences: flat-topped heads to 5 cm across, orange-yellow or orange changing to red, or white; peduncles: axillary, longer than the leaves; flowers: tubular, 4-parted, small; fruits: black (greenish when immature), fleshy, one-seeded drupes, 6 mm in diameter.
POISONOUS PARTS: The green, unripened fruit is very dangerous. Leaves of lantana also have yielded toxic principles upon extraction. Feeding studies indicate that lantana is quite poisonous. About 1% (green-weight basis) of body weight is sufficient for bovine toxic reactions. Fresh lantana fed to sheep produced acute symptoms and death within 5 days at about 2% of the animal's weight.
SYMPTOMS: Toxicosis produces gastrointestinal distress, vomiting, bloody-watery diarrhea, muscular weakness, ataxia, visual disturbances, lethargy, circulatory failure, and death. In acute cases lantana toxicity resembles atropine poisoning. The degree of poisoning depends on the amount of plant consumed and the degree of exposure to sunlight. Lantana contains toxins that cause organisms to react when exposed to the sun (photosensitization, see also Heracleum and Hypericum). Postmortem studies reveal degenerative changes in the liver and lesions of gastroenteritis. Edema and hemorrhages in some organs can occur in chronic cases.
POISONOUS PRINCIPLES: The alkaloid lantanin and a triterpene derivative, lantadene A, are implicated in poisonings.
CONFUSED TAXA: No other hanging-basket or potted plant from the greenhouse has the characteristics described.
SPECIES OF ANIMALS AFFECTED: Children have died after consumption of unripened berries. Beef and dairy cows are reported to succumb to browsing of lantana.
TREATMENT: (11a)(b); (26)