Monday, October 27, 2008

Ginkgo biloba: images and factoids.

Ginkgo biloba, turning leaves.

Ginkgo biloba has been known as the Maidenhair tree because its leaves are similarly shaped to the pinnae (leaflets) of maidenhair ferns (Adiantum spp.).


Maidenhair fern, Adiantum sp.

This fan-shaped leaf is unique among seed plants. Two veins enter at the leaf base and split dichotomously, and then again, and again, and so on, and so on.


Ginkgos are dioecious, having separate sexes. Male plants produce small, sporophyll-bearing pollen cones. Females produce two ovules at the end of stalks, one or both of which may develop into seeds, which are yellow-brown, fruit-like, and smell revolting if you step on them. For this reason most ginkgos used in landscaping are male.



Ginkgos were a widespread group in the supercontinent Laurasia -- the largest component of what was to become the present continents of the Northern hemisphere-- with recognizable fossil forms known from the Permian Period (270 million years ago) to the end of the Pliocene Epoch (1.8 million years ago). Historically Ginkgo biloba is known from China, where in the south and east it has been cultivated for centuries. It is unclear if wild-growing populations of Ginkgo in Zhejiang Province in eastern China are remnants of wild populations, or, perhaps more likely, were planted from cultivated trees. Whatever its recent history, like that other Chinese native, the dawn redwood, Ginkgo biloba is frequently referred to as a living fossil, because it is the only extant species of a once widespread group otherwise known only from the fossil record. How they must grow weary of that.


Large Ginkgo biloba, Paulik Park, Richmond BC.

The leaves turn bright yellow-green in autumn, and that’s when you tend to notice you have a ginkgo in the neighbourhood. But the yellow-tree window is small. The leaves tend to fall very quickly, almost all at once. Suddenly, it is time to rake.


3 comments:

Mother Nature said...

It is the most beautiful yellow and stunning when you see one at its peak.
Donna

Hugh said...

Yes, Mother Nature. They are spectacular.

Hugh said...

Staying in Touch -- Sorry, I don't know anything about the medicinal uses/usefulness of this plant.