Featured Plant

Sequoia sempervirens

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Scientific Name: Sequoia sempervirens, albino form

Common Names: Albino coast redwood, ghost tree

Family: Cupressaceae

Plant Type: Tree with a rare mutation, having shoots and leaves without chlorophyll.

Environment: Moist, semi-shaded, often in valleys. The coastal fog provides moisture from leaf drip during California's dry summers.

Bloom: Not relevant since this is a conifer and does not have flowers, however, here at the Garden the white shoots turn brownish and die back during winter.

Uses: If you are lucky enough to have one of these rare forms of coast redwood it would definitely be an accent specimen.

Other: In the wild these albino forms can be found in Henry Cowell Redwoods State Park, Redwoods State Park, and Big Basin State Park. However, their exact locations off the main trails are not publicized to protect these rare trees.

September

About

Sequoia sempervirens

Rarely for our monthly In Bloom editions do we focus on a Garden specimen so rare that we only have a single representative in our entire 55 acres. This month's feature is that exception.

Toward the back of our Redwood Grove, visible from the asphalt path, is a coast redwood specimen with a very rare, all-natural mutation. At this tree's base you will find a cluster of off-white stems and leaves which are considered "albino." Unlike most plants' leaves and young stems, they are not green. Look up into the canopy supported by the massive trunk connected to this cluster. The main trunk of the tree supports limbs with typical, green foliage. The only albino part of this specimen are these low stems.

True "albinism" is a condition in which pigments are absent from skin, and as such, this term is more appropriately used for animals, including humans. Albus is Greek for "white." Although "albino" is easier to pronounce and more familiar to us, in plants the more appropriate term for this condition is "achlorophyllous," that is, lacking chlorophyll, the pigment that makes most plants green.

Perhaps you recall that, unlike us, plants are able to make their own food - in the form of sugar - through the process called "photosynthesis?" Chlorophyll is the pigment in the chemical process of photosynthesis that catches light energy from the sun and transfers this energy through the photosynthetic process to make this sugar - food - for the plant. No chlorophyll, no photosynthesis, no sugar, no food. 

So how do these stems and leaves survive if they are unable to make their own food? Due to their inability to "photosynthesize," it is impossible for them to survive on its own. These off-white stems and leaves are only alive because they are attached to the massive trunk behind them that supports a green, chlorophyll-rich canopy up above. The sugar created through photosynthesis far above in the tree's canopy travels all the way down through the large trunk and feeds the albino stems at ground level. In a sense, these low stems are parasitic; unable to feed themselves, they rely entirely on the rest of the tree to survive! 

For coast redwoods, this phenomenon is known to occur in the wild in only very, very small numbers, only a microscopic fraction of 1% of all the redwood trees living in the coast wilderness from the southern tip of Oregon to California's Monterey County. Varying sources report that between 60 and 100 individual albino trees are known to exist out of the well-over 100,000 acres of coast redwood forest in the State. Only one of these extreme rarities is known to exist in a botanical garden… 

 

IN BLOOM CONTRIBUTORS: Text by Corey Barnes. Photos by Mona Bourell, Brendan Lange, and Joanne Taylor.

ARCHIVES: IN-BLOOM

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Phone: (415) 661-1316

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San Francisco Botanical Garden is a public/private partnership between San Francisco Botanical Garden Society and the San Francisco Recreation and Park Department.