'monomorphic-leaved' is a modern compound formed in English from the Greek-derived combining form 'monomorphic' (from Greek 'mono-' + 'morphē') meaning 'of one form' and the English adjective-forming use of 'leaved' (from 'leaf') to indicate having leaves.

'monomorphic' comes from Greek roots 'mono-' ('one') and 'morphḗ' ('form'); it entered scientific and descriptive English usage as 'monomorphic' and was later combined with the English element 'leaved' to make the compound 'monomorphic-leaved'.

Initially the Greek root combination referred generally to 'one form'; in botanical English the compound eventually came to mean specifically 'having leaves of a single form'.