ginkgo

ginkgo or maidenhair tree, tall, slender, picturesque deciduous tree (Ginkgo biloba) with fan-shaped leaves. The ginkgo is native to E China, where it was revered by Buddhist monks and planted near temples. A "living fossil," the ginkgo is the only remaining species of a large order (Ginkgoales) of gymnosperms that existed in the Triassic period. Its form has not changed in millions of years, as is shown by fossils widely scattered over Europe, North and South America, and Asia. The ginkgo is valued today as a street tree, being exceptionally tolerant of smoke, low temperatures, and minimal water supply. The male and female strobile (see cone) are borne on separate trees. The "fruit," botanically a seed, is surrounded by a malodorous pulp, making the male trees more desirable as ornamentals; however, the seed kernel is highly esteemed in East Asia as a food. The herbal remedy ginkgo biloba, an extract of ginkgo leaves, is said to enhance concentration and short-term memory. The ginkgo is classified in the division Pinophyta, class Ginkgoopsida, order Ginkgoales, family Ginkgoaceae.

Tree (Ginkgo biloba, family Ginkgoaceae) that is the only living representative of the gymnosperm order Ginkgoales. Native to China, it is often termed a living fossil because it is unclear whether uncultivated groups can be found in the wild. It has been planted since ancient times in Chinese and Japanese temple gardens and is now valued in many parts of the world as an attractive, fungus- and insect-resistant ornamental tree. It tolerates cold weather and, unlike most gymnosperms, can survive the adverse atmospheric conditions of urban areas. Pyramidal in shape, it has a columnar, sparingly branched trunk. The light-coloured wood, soft and weak, has little economic value. The fan-shaped, leathery leaves, most divided into two lobes by a central notch, resemble the leaflets of the maidenhair fern. The silvery nut, when roasted, is considered a delicacy. Studies have suggested that Ginkgo biloba supplements can enhance memory function in the elderly and delay the onset of Alzheimer disease.

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The Ginkgo-toothed Beaked Whale (Mesoplodon ginkgodens) is a poorly known species of whale even for a beaked whale, and was named for the unusual shape of its dual teeth. It is a fairly typical looking species, but is notable for the males not having any scarring.

Physical appearance

Ginkgo-toothed Beaked Whales are more robust than most mesoplodonts, but otherwise look fairly typical. Halfway through the jaw, there is a sharp curve up where the ginko leaf shaped tooth is. Unlike other species such as Blainville's Beaked Whale and Andrews' Beaked Whale, the teeth do not arch over the rostrum. The beak itself is of a moderately long length. The coloration is overall dark gray on males with light patches on the front half of the beak and around the head, and also have small white spots on the bottom of the tail, but the location may be variable. Females are a lighter gray and have countershading. Both of the genders reach 4.9 meters (16 feet) in length. They are around 2.4 meters long (8 feet) when born.

Population and distribution

This beaked whale has had less than 20 strandings off the coasts of Japan, California, the Galapagos Islands, New South Wales, New Zealand, Sri Lanka, the Maldives, and the Strait of Malacca. Its range is essentially tropical and temperate waters in the Indian and Pacific Ocean. There is no way to judge the population.

Behavior

The males probably do not engage in combat and the species probably feed on squid and fish. No other information is known.

Conservation

The only observations of this species while alive have come from hunters off the coasts of Japan and Taiwan, who occasionally take an individual. They are also affected by drift gillnets.

References

• Encyclopedia of Marine Mammals. Edited by William F. Perrin, Bernd Wursig, and J.G.M Thewissen. Academic Press, 2002. ISBN 0-12-551340-2
• Sea Mammals of the World. Written by Randall R. Reeves, Brent S. Steward, Phillip J. Clapham, and James A. Owell. A & C Black, London, 2002. ISBN 0-7136-6334-0

External links

• Cetaceans of the World
• CMS
• Whale & Dolphin Conservation Society (WDCS)