'achlamydeous' originates from Greek, specifically the word 'achlamydos,' where 'a-' meant 'without' and 'chlamys' meant 'cloak or covering.'

'achlamydos' transformed into the Latin word 'achlamydeus,' and eventually became the modern English word 'achlamydeous.'

Initially, it meant 'without a covering,' but over time it evolved into its current meaning of 'lacking a floral envelope or perianth.'