Thelymitra x irregularis is a hybrid between T. ixioides and T. rubra/carnea. The T. ixioides parentage confers the tufts to the column and spotting on the tepals. The T. rubra/carnea gives the plant its pink colouration and makes the column tufts fleshier and yellow. I observed the hybrid in Melbourne’s south east where all three species grow in proximity.
Comparison of the columns between T. ixioides (left), T. x irregularis (centre), and T. rubra (right)