Large strain-energy arising from lattice mismatch allows one-dimensional heteroepitaxial growth of In(chi)Gal(1-chi)As on silicon substrates without any catalyst or pattern assistance. In this paper, we show that in contrast to nanowires (NWs) grown by metal-catalyzed vapor-liquid-solid mechanism, strain-induced In chi Ga1-chi As NWs have several unique morphological features including no tapering, slight bending, and composition-dependent NW height saturation. Although small fluctuation exists, no systematic composition variations are observed over the entire In chi Ga1-chi As NW length within the resolution of the energy-dispersive X-ray spectroscopy analysis.