How to adjust the legend of a graph in this case?

Hi

In the below image each line has 3 segments which are represented with 3 colors. Lines are represented with *, - and + for 1st, 2nd and 3rd respectively. The problem is that in legend it is showing only one symbol with varying color which is not true in this case. In the legend, I want to show the corresponding symbol without color.

Please suggest me the code

      figure
        axes('FontSize', 20);
        xlabel('1/T');ylabel('ln(g({\alpha})/T^{2}');title('@20^{0}C');  
        line_fewer_markers(T_3,O1_3,10,'-g*')
        line_fewer_markers(T_6,O1_6,10,'-k*') 
        line_fewer_markers(T_8,O1_8,5,'-r*')
        line_fewer_markers(T_3,O2_3,10,'-g-')
        line_fewer_markers(T_6,O2_6,10,'-k-') 
        line_fewer_markers(T_8,O2_8,5,'-r-')
        line_fewer_markers(T_3,O3_3,10,'-g+')
        line_fewer_markers(T_6,O3_6,10,'-k+') 
        line_fewer_markers(T_8,O3_8,5,'-r+')
        legend(' 1st ','2nd', '3rd')
.

Thanks