Really the Anubias commonly get that due to age. Like was said before the leaves just last longer cause they grow slower than most plants. Java Fern have that problem also.
The other kind I don't know the name of but is what has been mistaken for hair algae.
You should have the light(s) on for less time each day as that is what makes this kind grow. I have mineon for 6.75 hrs per day reduced from 7.5 hrs to try to get that kind
a bit less than I had it before. I like that kind(both really) and keep high light in my tank to make it grow for me. I just don't want it to take over. So now I'm learning to "control" it so I can have just as much as I want but not more of it.
Knowing what kind and how much light you have would make it easier to suggest
how much to reduce it to. Also how far it is from the top of the water to the bottom of the tank(top of gravel) would help.