'unequal-stamened' originates from English, formed by the adjective 'unequal' (from Old French/Latin) and the noun 'stamen' (from Latin 'stamen'), where 'unequal' meant 'not equal' and Latin 'stamen' originally meant 'warp, thread' and later was used in botanical Latin for the male reproductive organ of a flower.

'stamen' entered English from Latin 'stamen' (via Neo-Latin botanical usage) and 'unequal' came into English via Old French/Middle English from Latin 'inaequalis'; in modern botanical English these elements were combined to form the compound adjective 'unequal-stamened'.

Initially the components meant 'not equal' (unequal) and 'thread/warp' (stamen); over time the compound evolved into a specialized botanical term meaning 'having stamens of unequal lengths'.