Weeds of Wednesday: Pea #3

Rosary pea (Abrus precartorius) was flowering at the northern end of Jungle Trail near the Pelican Island National Wildlife Refuge (PINWR) when we visited on 10-8-2023. This member of the pea family, Fabaceae, is an invasive pest plant in Florida and can smother other plants. It is thought to be native to India.

The flowers have five purple petals. The upper 2 petals are fused to form a standard, and the lower petal is folded to form the keel. 

Ants, beetles, and other insects visit the flowers and mostly remain within inflorescence clusters of the same plant, ensuring effective self-pollination. Some insects are more interested in the extrafloral nectaries and/or the abrusosides A-D, four sweet-tasting triterpene glycosides found in the leaves and leafy-twigs of Abrus species. You will find these insects on the young leafy twigs, leaf and stem angles (axils) rather than in the flower clusters.

Once pollinated, a cluster of pods are formed …

Each pod splits open length-wise (dehisces) to expose hard, glossy red seeds with black “eyes” that are very poisonous. They contain abrin, a very powerful plant protein that inhibits protein production in cells and can be deadly. Despite their toxicity, these seeds were used in rosary beads and jewelry giving rise to common names like rosary pea, prayer beads, precatory (prayer) bead, jequirity, crab’s eye, black-eyed Susan, red beadvine. The species name precatorius is derived from the Latin word precari, which means to pray and references the historic use of the seeds for rosary beads.

Other common names reference the sweet licorice-like taste of the edible roots and stems: false licorice, Indian licorice, licorice plant, and licorice vine. Given the toxic properties of this best, it would be best to not indulge.

The hard-coated seeds can last for decades in the soil. Pictured above is a rosary pea seedling. When young, they are easy to pull up. Once they get growing (and this vine grows fast), they are very deep-rooted and difficult to pull up. Please do all that you can (i.e., remove the seeds pods, cut back the vine, pull it up whenever possible) to vanquish this evil invader.