The Cursed Torch is a torch added in 1.1 which can be placed under water. To craft these, the player must use 1 Cursed Flame along with 33 Torch. It functions at 80% of the brightness of a regular torch.
Now with the Cursed Torch introduced, glowsticks have become somewhat useless, as these torches will remain in water, and, unlike glowsticks, can't be picked up if you pass through them (unless of course a player breaks them). However, if a player needs to see a further distance underwater, glowsticks are the better choice, as they can of course be thrown. One of the only thing these two have in common are that they seem to have a despawn timer like glowsticks when underwater (Bug?) and also give off a greenish glow like glowsticks.
Not only can these be placed in both still and flowing water, but also in the path of both resting and flowing lava.