Ginkgo is a large deciduous tree with a diameter at breast height of up to 4 meters. The bark of saplings is nearly smooth and light gray. The bark of large trees is grey-brown, irregularly split and rough; it has long branches and slow-growing branches. Spur-shaped short branches.
The crown is conical in young and mature years, and broadly ovate in old age; the branches are nearly whorled and extend diagonally upward (the large branches of female plants are often more spread out than those of male plants); the long branches of annuals are light brown and yellow, and those of biennials and above are light brown. Turns gray with fine longitudinal cracks; short branches are densely covered with leaf scars, black and gray, and long branches can also grow on short branches; winter buds are yellowish brown, often oval, with blunt tips.
The leaves are alternate, radially scattered on long branches, and 3 to 5 in clusters on short branches. They have slender petioles, fan-shaped, light green on both sides, hairless, and have many forks. Veins juxtaposed, more or less notched or 2-lobed on the broad top margin, 5-8 (-15) cm wide, with many forked and scalloped veinlets. Scattered on long branches and clustered on short branches. Its leaf veins are in the form of "bifurcated veins".
On long branches, there are often 2 lobes, the base is wide and wedge-shaped, and the stalk is 3-10 (mostly 5-8) cm long. The leaves on saplings and sprouting branches are often larger and deeply lobed (the leaves are as long as 13 cm, 15 cm wide), sometimes the lobes are divided again (this is similar to the leaves of more primitive fossil species), the leaves are spirally scattered on the annual growth branches, and 3-8 leaves are clustered on the short branches, and the leaves fall off in autumn. turns yellow before.
The flower bulbs are dioecious and unisexual, growing in clusters in the axil of the scale-like leaves at the top of short branches. The male cones are catkin-like, drooping, with loosely arranged stamens and short stalks. The anthers are often 2, oblong, the chamber is longitudinally split, and the anthers are not separated.
The female flower cone has a long stalk, and the stalk end is often divided into two forks, rarely 3-5 forks or not at all. Each fork has a disk-shaped pearl base on which the ovule is born, usually only one. The ovules at the fork end develop into seeds, which are pollinated by wind. When its male flower pollen germinates, it produces only two ciliated and swimming sperm.
Blooms in April and matures in October. The seeds are long-stemmed and drooping. They are often oval, long-obovate, oval or nearly spherical, 2.5-3.5 cm long, 2 cm in diameter, medium Seed coat is bony, white, often with 2 (rarely 3) longitudinal ribs; inner seed coat is membranous.
The outer testa is fleshy, yellow or orange when ripe, covered with white powder on the outside, and has smelly leaves; the middle part is white and bony, with 2-3 longitudinal ridges; the inner testa is membranous and light red. Brown; endosperm is fleshy, sweet and slightly bitter.
Cotyledons 2, rarely 3, not unearthed during germination, primary leaves 2-5, wide strip, about 5 mm long, 2 mm wide, apex slightly concave, 4th or 5th After rising, the leaves are fan-shaped, with a deep crack and irregular wavy notch at the apex. The petiole is 0.9-2.5 cm long; there is a taproot.
Extended information:
Edible value
The seeds are edible (eating too much can cause poisoning) and medicinal purposes. The fleshy outer testa of the seeds contains ginkgo acid, ginkgo alcohol and ginkgo phenol, which are toxic. The bark contains tannins. Ginkgo is famous for its ginkgo fruit, which is rich in nutrients and contains crude fat 2.16, starch 62.4, sucrose 5.2, reducing sugar 1.1, nuclear protein 0.26, minerals 3, and crude fiber 1.2.
As well as vitamin C 66.8-129.2 mg/100g, vitamin E 6.17-8.05 mg/100g, riboflavin, carotene, carotenoids, anthocyanins, and 17 kinds of amino acids, Ginkgo alcohol (10-nonacosanol), ginkgo ketone, octacosanol, B-sitosterol, stigmasterol, alkaloids, etc. Trace elements include Fe, Cu, Mn, Zn and major elements Ca, Mg, etc. Has high edible value.
Eating ginkgo fruit can inhibit bacteria and sterilize, dispel diseases and relieve coughs, resist waterlogging and inhibit insects, stop turbidity and lower serum cholesterol. In addition, Ginkgo can reduce lipid peroxidation levels, reduce freckles, moisturize the skin, and create a beautiful appearance. The flavonoid glycosides and flavonols in ginkgo leaves are free radical scavengers, which can protect dermal cells, improve blood circulation, and prevent cells from being oxidized and causing wrinkles.
Ginkgo is one of the herbs with anti-active gene abilities. Ginkgo is effective in protecting lipids (components of cell membranes) from free radical damage.
But it also contains minor toxic substances: hydrocyanic acid, ginkgo acid, hydrogenated ginkgo acid, hydrogenated ginkgo acid, ginkgo phenol, and ginkgo alcohol. Therefore, you should pay attention to how you eat ginkgo when eating it. If cooked and eaten, ginkgo acid and ginkgo acid can be decomposed, and hydrocyanic acid has a low boiling point and is easy to volatilize and remove, so the toxicity of cooked ginkgo is less.
In order to prevent ginkgo poisoning, cooked food and eating less are the fundamental methods. The medical community believes that raw ginkgo should be limited to about 10 pills a day. Excessive consumption can cause symptoms such as abdominal pain, fever, vomiting, and convulsions. Some people like to drink ginkgo leaves soaked in water, but this has certain risks. Ginkgo leaves contain toxic ingredients, and taking them in high doses or for a long time can harm your heart health.
Reference: Baidu Encyclopedia-Ginkgo