The rosary pea or jequirity bean (Abrus precatorius Linnaeus) is native to India, but has become a pan-tropical nuisance species. The genus is derived from the Greek Habrus meaning graceful, elegant, or delicate; the species epithet comes from precator, one who prays. The vine has a perennial root system and airy, delicate-looking leaves with eight to sixteen leaflets. In one season, the vine can grow 20 feet, twining over other plants. It is almost impossible to eradicate.

In India, the seed was called retti or rati. The seeds are uniform in size, each weighing very close to 2.1875 grains (1 grain equals 0.002286 ounce equals 0.0648 gram). Retti-weights were used to weigh gem stones. According to Mrs. Grieve (A Modern Herbal, 1931, reprinted 1996), "The weight of the famous Koh-i-noor diamond was ascertained by means of these seeds."

Rosary pea seeds are scarlet and black. The brightly colored seeds were strung for necklaces and rosaries; one of the main reasons it was introduced worldwide. Unfortunately, teething toddlers sitting in their mother's or grandmother's lap and chewing on her necklace/rosary were poisoned. Rosary pea seeds are considered one of the most toxic, if not the most toxic, plant part.

The Merck Index (11th Edition, 1989) states that seeds contain Abrus agglutinin, a hemagglutinating lectin, and abrins a through d, disulfide-linked polypeptide chains (proteins). According to Lewis and Elvin-Lewis, the symptoms of Abrus poisoning are severe stomach pain, nausea, diarrhea, coma, circulatory collapse, and death. (Medical Botany, Plants affecting man's health, 1977) A single seed can be fatal to an adult. Farm animals are equally affected by the toxins.