'atypical-flowered' originates from Modern English, specifically a compound of 'atypical' and 'flowered', where 'a-' (from Greek) meant 'not' and 'typikos' (Greek) meant 'of a type', while 'flower' comes via Old English/Middle English from Latin 'flos, floris' meaning 'blossom'.

'atypical' entered English in the 19th century from Greek elements (a- + typikos) through modern formation; 'flower' evolved from Old English 'blōma' and Latin 'flos' via Middle English 'flour/flower'. The hyphenated compound form 'atypical-flowered' is a Modern English descriptive formation combining these elements.

Originally the components meant 'not typical' and 'having blossoms'; over time they combined into a specialized adjective meaning 'having flowers that deviate from the usual type or form'.