Introduction
Kingdom: Plantae
Division: Ginkgophyta Class: Ginkgoopsida Order: Ginkgoales Family: Ginkgoaceae Genus: Ginkgo Species: G. biloba |
Ginkgo biloba is the sole surviving species of Ginkgoales, though during the Triassic and Jurassic it was a diverse order[15][16]. In the wild it is currently only found in eastern China. Based on fossil evidence found over Asia, Europe, and both Americas, it doesn't appear to have undergone significant changes in millions of years[15]. They are quite rugged, being popular street tree's due to being tolerant of smoke, low temperatures, and minimal water supply[15], and also evidenced by at least six G. biloba trees surviving to this day in Hiroshima, apparently healthy, after the bombing in 1945[19].
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Morphology & Reproduction
G. biloba is a gymnosperm, with the male and female cones are produced on separate trees (no bisexual trees)[15]. Unlike typical gymnosperms, the female trees don't bear cones[18], instead two ovules are produced at the end of stalks (see picture). After developing into seeds, they form an odoriferous fleshy outer layer ("sarcotesta"), that attracts mammalian scavengers, assumed to be by mimicking the smell of carrion. Seeds shed of their sarcotesta germinate faster, which might mean that animal dispersal/digestion plays a role in seed distribution[17]. The leaves are fan-shaped, with vascular veins branching at the start of the leaf to cover the area (furthering the resemblance to a fan, see picture)[16].
Left: ovules on a female plant (no cones), and leaves
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References
[15]Ginkgo. (2013). Columbia Electronic Encyclopedia, 6th Edition, 1.
[16]http://www.ucmp.berkeley.edu/IB181/VPL/CorCon/CorCon2.html
[17]del Tredici, P. (2007). The Phenology of Sexual Reproduction in Ginkgo biloba: Ecological and Evolutionary Implications. Botanical Review, 73(4), 267-278.
[18]http://en.wikipedia.org/wiki/Ginkgo_biloba
[19]http://kwanten.home.xs4all.nl/hiroshima.htm
[16]http://www.ucmp.berkeley.edu/IB181/VPL/CorCon/CorCon2.html
[17]del Tredici, P. (2007). The Phenology of Sexual Reproduction in Ginkgo biloba: Ecological and Evolutionary Implications. Botanical Review, 73(4), 267-278.
[18]http://en.wikipedia.org/wiki/Ginkgo_biloba
[19]http://kwanten.home.xs4all.nl/hiroshima.htm