Amianthium is a monotypic genus of perennial monocot plants in the family Melanthiaceae, comprising a single species: Amianthium muscitoxicum, commonly known as fly poison or stagger grass. Native to the eastern United States, the genus was first formally recorded by Thomas Walter in his Flora Caroliniana in 1788.
Plants grow 1–4 feet tall, with long, thin basal leaves reaching over 12 inches and greatly reduced stem leaves. Between May and July, A. muscitoxicum produces small white flowers arranged in an indeterminate bracteate raceme — opening from the base upward — that turn greenish or purplish with age. By late summer or fall, the inflorescence gives way to small, bright orange fruits.
The entire plant is highly toxic. Four alkaloids were isolated from it in 1953: jervine, amianthine (an alkamine), and two unknown ester alkaloids. These compounds occur throughout the plant but are most concentrated in the bulbs. Ingestion causes serious symptoms in livestock and humans alike — excessive salivation, nausea, rapid and irregular pulse, weakness, and difficulty walking — and can be fatal within an hour. This toxicity gives rise to the common name "stagger grass."
Despite its danger, A. muscitoxicum was put to practical use by early colonists, who mixed the ground bulb with molasses or honey to create fly bait — the source of its other common name, "fly poison." In its native range, the plant grows in oak forests, bogs, low pinelands, savannas, meadows, and sandhills, typically in partial shade with limited direct sunlight.
Etymology
The genus name Amianthium is derived from Greek. The sole species epithet muscitoxicum is a direct Latin rendering of "fly poison": muscae meaning flies and toxicum meaning poison, reflecting the plant's long use as a fly killer.
Distribution
Amianthium muscitoxicum is native to the eastern United States, ranging from New York south to Florida and west to Missouri and Oklahoma. It grows in oak forests, bogs, low pinelands, savannas, meadows, and sandhills, generally in partial shade.
Ecology
The plant favors partial shade, tolerating only 1–2 hours of direct sunlight per day. It naturally associates with longleaf pine, willow oak, mountain laurel, blueberries, galax, heartleaf, foamflowers, Solomon's seal, black cohosh, and various grasses and small woodland perennials.
Cultural Uses
Early colonists exploited the bulb's toxicity as a fly control method — grinding the bulbs and mixing them with a sweet substance such as molasses or honey to attract and incapacitate flies. This practice gave the plant its most widely used common name, "fly poison." The common name "stagger grass" derives from the staggering gait observed in livestock that ingested the plant.
Taxonomy Notes
Amianthium is monotypic, containing only A. muscitoxicum. It is placed in the family Melanthiaceae (order Liliales), a family of monocots that also includes the genera Veratrum, Zigadenus, and Trillium. The genus was first published in association with Thomas Walter's 1788 Flora Caroliniana, predating modern phylogenetic treatments that settled it in Melanthiaceae.
