HMSF threshold (dashed line; M[M_⊙] = 1053 (R[pc])^1.33) for molecular clouds using the MR (science) sample. The y axis represents M/M_crit, where M_crit = 1053 (R[pc])^1.33 is the HMSF threshold. The coloured ellipses encompass approximately 99.7% of the data points and represent three-sigma levels for the cloud morphologies, which are indicated by the legends in the four plots. The clouds with HMSF tracers (Table 9) are denoted by a star (⋆).