Looks like staghorn algae to me. If you have any liquid CO2 such as Seachem Excel, get a syringe or a pipette, turn the filter off, spray it directly onto the algae, and turn the filter back on. It’ll turn red and die off in a couple of days.
Alternatively, I would cut the infected leaves off and make sure you have your nutrients and lights balanced. This includes CO2 if you’re using it. A low flow or “dead zone” area is another cause
TheArabCanadian 
Looks like staghorn algae to me. If you have any liquid CO2 such as Seachem Excel, get a syringe or a pipette, turn the filter off, spray it directly onto the algae, and turn the filter back on. It’ll turn red and die off in a couple of days.
Alternatively, I would cut the infected leaves off and make sure you have your nutrients and lights balanced. This includes CO2 if you’re using it. A low flow or “dead zone” area is another cause
Doesnt look like it, i currently struggle with it in several tanks and it looks nothing alike.