Random color shades of a specific color

how to get a random color in shades of a specific color, e.g. brown, green

Im using this and it's cool but I don't understand how it works. This code draws all the shades for me, and I don't want the grass to be purple ;-P

rgbEx(

lerp(50, random(100), 0.4),

lerp(50, random(100), 0.4),

lerp(50, random(100), 0.4)

)

rgbEx just defines the three color channels Red, Green and Blue and the code you use just mixes in random amounts of color (in a weird way I may add)

I´d go ahead and use fixed values like rgbEx(50,20,5) and find colors you like, then you can add code to add some variance like rgbEx(50+random(0,10), 20+random(-5,5), 5)

100 means full color, 50 means 50% color, 0 means no color at all.