What is the difference between a rose comb and single comb leghorn

[chickengal]

My daughter is entering her chickens into the fair and there is a catagory for bantam single comb clean legged leghorn and a different catagory for bantam rose comb clean legged leghorn. What is the difference. What does he single comb look like?

 

[geosheets]

I don't remember where I originally found this (maybe here on BYC) but I saved it on my computer for future reference

 

[guinealeghorn]

Hi I just wanted to say that the picture of combs is very helpful. Thank you for posting it!