Have you ever heard the one about Alice Algae and Freddie Fungus? Seems they took a lichen to each other.
Lichens are everywhere here on Cape Cod and many people are confused as to whether they are an algae or a fungus. They are neither, actually, but sort of a combination of the two. They get the advantage of the symbiotic qualities of the fungus as well as the photosynthetic abilities of the algae and can survive in what may otherwise be very tough and hostile habitats.
For more information check out Gil Newtons' Cape Cod Coastal Ecology Website.