Asarum acuminatum

Asarum acuminatum is a species of flowering plant in the family Aristolochiaceae, commonly known as the hydra ginger. It is native to the north-central and east-central regions of the United States, where it occurs primarily in rich deciduous forests.^[1][2]

Asarum acuminatum is a perennial, rhizomatous herb that grows low to the ground in forest understories. The leaves are typically paired, broadly cordate, and arise directly from the rhizome.

The flowers are solitary and borne at ground level. They are typically yellow to bronze in color and lack prominent leaf mottling. The calyx tube is approximately 10–20 mm long, with calyx lobes that are long-caudate (15–35 mm), initially erect to ascending at anthesis and becoming more spreading as the flower matures.^[2]

Asarum acuminatum was originally described as Asarum canadense var. acuminatum by William Willard Ashe in 1897 and was later elevated to species rank by Eugene P. Bicknell in 1898.^[1]

Recent treatments such as Plants of the World Online and the Flora of the Southeastern United States accept A. acuminatum as a distinct species.^[1][2] However, a 2025 master's thesis by Brett Lambert, using morphological and genome-wide SNP data, concluded that A. acuminatum substantially overlaps with A. canadense and is best treated as Asarum canadense var. acuminatum, while supporting A. reflexum as a distinct species.^[3]

Asarum acuminatum is native to the central and eastern United States, including Alabama, Arkansas, Illinois, Indiana, Iowa, Kentucky, Michigan, Minnesota, Missouri, North Carolina, Tennessee, Virginia, and Wisconsin.^[1]

It occurs primarily in rich deciduous forests, often in mesic, shaded habitats with well-developed soils.^[2]

Flowering typically occurs from April to May.^[2]

Like other species in the genus Asarum, A. acuminatum is a low-growing forest herb adapted to shaded environments. Its ground-level flowers are thought to be pollinated by small insects, and its seeds are likely dispersed by ants (myrmecochory), a common trait in the genus.

The circumscription of Asarum acuminatum remains an area of ongoing study. Some earlier treatments, including the Flora of North America, included it within Asarum canadense.^[1] More recent regional floras have recognized it as distinct based on morphological differences in floral structure and geographic patterns.^[2]