American sweet flag

Description

Acorus americanus, the American sweet flag, is an emergent wetland plant native to the northern United States and Canada. This perennial plant has bright green blade-shaped leaves that arise directly from the rhizomes and sheath into each other at the base. Additionally the blades have 2-6 raised veins, and a swollen center when viewed in cross section. The foliage has a citrus-like spicy aromatic quality, and can be used to flavor beer. It is a flowering plant with inconspicuous flowers that are arranged on a lateral spadix (a thickened, fleshy axis) and the fertilized flowers produce berries with a jelly inside. This plant is protected as a state endangered species in Pennsylvania. The name "Acorus" is derived from the Greek word 'acoron', a name used by Dioscorides, which in turn was derived from 'coreon', meaning 'pupil', because it was used in herbal medicine as a treatment for inflammation of the eye. The species name, "americanus" simply indicates that this is an American species of this genus, differentiating it from the very similar European and western Asian species Acorus calamus. Acorus is a genus of monocot flowering plants. This genus was once placed within the family Araceae (aroids), but more recent classifications place it in its own family Acoraceae and order Acorales, of which it is the sole genus of the oldest surviving line of monocots. Some older studies indicated that it was placed in a lineage (the order Alismatales), that also includes aroids (Araceae), Tofieldiaceae, and several families of aquatic monocots (e.g., Alismataceae, Posidoniaceae). However, modern phylogenetic studies demonstrate that Acorus is sister to all other monocots. Common names include calamus and sweet flag. The genus is native to North America and northern and eastern Asia, and naturalised in southern Asia and Europe from ancient cultivation. The known wild populations are diploid except for some tetraploids in eastern Asia, while the cultivated plants are sterile triploids, probably of hybrid origin between the diploid and tetraploid forms.