Achyranthemum is a genus of flowering plants in the daisy family Asteraceae (order Asterales), commonly known as the chaff flowers. Described by Nicola Bergh in 2019 in the South African Journal of Botany, the genus was segregated from Syncarpha based on molecular evidence showing it represents a separate evolutionary lineage. All seven species are native to South Africa.
Members of Achyranthemum are subshrubs with soft wood. Their leaves are rigid and densely covered in wooly gray-white hairs, with acute tips that are often hooked. The flower heads (capitula) are homogamous — composed of a single flower type — and are surrounded by shiny bracts that range from white to cream or yellow, frequently tinged pink. The stereome (hardened tissue) at the base of each bract is undivided. The anthers are slender and positioned at the tips of caudicles (slender appendages). The fruit is a cypsela bearing roughly hemispherical hairs, and the pappus (the modified calyx) consists of somewhat rough bristles fused into a ring at their base. Notable species include Achyranthemum paniculatum and Achyranthemum argenteum.
Etymology
The genus name Achyranthemum is derived from the Greek words achyron (chaff) and anthos (flower), referring to the chaff-like appearance of the plant parts. This etymology also gives the genus its common name, the chaff flowers.
Distribution
Achyranthemum is endemic to South Africa. All seven recognized species are native to the Cape region and surrounding areas of the country.
Taxonomy
Achyranthemum was first described by South African botanist Nicola Bergh in 2019 in the South African Journal of Botany. It was segregated from the closely related genus Syncarpha after molecular phylogenetic analysis demonstrated that the species placed in Achyranthemum constitute a distinct evolutionary lineage. The genus currently includes seven species, with the authority for each attributed to N.G.Bergh. GBIF places the genus in family Asteraceae, order Asterales.
