An albino redwood tucked away in Golden Gate Park.
Although albino plants are not an uncommon mutation as far as plant mutations go, most plants that do not produce chlorophyll can not survive beyond germination. Once albino seedlings have exhausted the energy stores inside their seed, they cannot produce more nutrients.
Redwoods, however, have the rare quality of sap exchange through their roots; a parent tree will share nutrients with saplings through its root system, allowing albino redwoods to live in tandem with older, established trees. Because the white leaves of an albino redwood do not survive strong sunlight, this often looks like a small offgrowth or bush at the trunk of a larger tree.
Albino redwoods are generally considered parasitic, but recent scholarship has noted that they are uniquely adapted to sequestering high amounts of toxic materials and heavy metals (the same materials that may cause mutations) because of the higher rate of transpiration in mutated stomata.
Albino redwoods are not a unique phenomenon, but a rare one - roughly 400 are recorded, and their locations are kept a closely-guarded secret. It is this secrecy that makes the botanical garden redwood so special. It is a tree you can visit.