Tamarugal - Prosopis tamaruga - grows in a part of Chile with effectively no rain. Although this
http://en.wikipedia.org/wiki/Prosopis_tamarugo says it harvests fog, its main source of water is ground water from seepage. It is unusual because it can use very saline ground water, and grow on salt pans. Because it grows in depressions with relatively shallow ground water, it doesn't need hugely long roots. There has been some restoration of the forest in some places.
Prosopis is the mesquite family, closely related to acacias.
I've also seen cactus growing in rain-free parts of Chile, which are obligate fog harvesters. They grow in a narrow altitude band where the fog is particularly common/dense.