Parasitic plants do not grow in the ground, instead they grow on other plants. See: http://en.wikipedia.org/wiki/Parasitic_plant
List of examples: http://www.parasiticplants.siu.edu/ParasiteFood.html
So would it be like a mushroom which does not grow from the ground? Or would it be like a plant because A: It uses photosynthesis, and B: It grows on a living plant, which in turn grows on the ground?
Not all parasitic plants use photosynthesis, but they do grow on a plant that uses it, does that change the answer?
Also, what bracha is the plant itself, not just the fruit?