Hex #558b55 or rgb(85,139,85) in RGB space is the tint of green. It has hue angle of 120.00 degrees, value = 55 and saturation = 39. #558b55 can be obtained by mixing 3 colors: 1 drop of red, 1 drop of cyan, 1 drop of green.
Nearest safe hex - #669966. Below you can see the block with #558b55 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #558b55 to the mixer and play with it.