Achyranthes is a genus of flowering plants in the family Amaranthaceae (order Caryophyllales), commonly known as chaff flowers. The genus encompasses around 33 accepted species of herbaceous plants and subshrubs that typically produce slender, erect spikes of small, inconspicuous flowers. Each flower is solitary and fertile, a defining characteristic of the genus.
The genus has a wide distribution spanning tropical and subtropical regions of Africa, Asia, the Mediterranean basin, Hawaii, and Pacific island groups including the Marquesas and Mangareva. Hawaiian species — including Achyranthes divaricata, A. humile, and A. sandwicensis — are known locally by the Hawaiian name kuluʻī.
The circumscription of Achyranthes was significantly revised in 2024, when a morphological and phylogenetic analysis by Vanessa Di Vincenzo and colleagues merged the former genus Achyropsis and the Hawaiian endemic genus Nototrichium into Achyranthes, rendering it monophyletic. Several species, particularly Achyranthes aspera, have longstanding uses in traditional medicine across their native ranges.
Distribution
Achyranthes species are distributed across tropical and subtropical regions of Africa, Asia, the Mediterranean (notably A. sicula), the Hawaiian Islands, and Pacific island groups including the Marquesas and Mangareva. The Hawaiian species — A. divaricata, A. humile, and A. sandwicensis — are recognized as endemic to the archipelago and were previously placed in the genus Nototrichium before being merged into Achyranthes in 2024.
Taxonomy Notes
Achyranthes was historically a narrower genus, but a 2024 morphological and phylogenetic study by Di Vincenzo, Berendse, Wondafrash, and Borsch expanded its circumscription by sinking Achyropsis and the Hawaiian genus Nototrichium into Achyranthes to achieve monophyly. The genus belongs to the family Amaranthaceae within the order Caryophyllales. Thirty-three species are currently accepted under this revised treatment.
