ΔE 18.3, loose: different enough that you should pick on purpose. Mud Brown is a little lighter, much more muted than Dryad Brown.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 18). Mud Brown is a little lighter, much more muted than Dryad Brown.
The same difference applies the other way round: Dryad Brown is a little darker, much more saturated.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Dryad Brown on the colour wheel See Mud Brown on the colour wheel
All matches: Dryad Brown equivalents · Mud Brown equivalents