[C#] Distance Units of a Layer

Hello,

I am developing an ArcGIS desktop addin. I am attempting to get the distance units (ft, mm, km, etc.) from a layer in my .mxd and display it on a windows form. How can I do this? I can access the distance units of a map by using IMap.DistanceUnits, but I have had trouble accessing the distance units of an individual layer.