Ginkgo trees are about several centimeters longer than one year.

Ginkgo biloba is a deciduous tree with a DBH of 4 meters. The bark of young trees is nearly smooth, light gray, and the bark of big trees is grayish brown, irregular and rough longitudinally. There are long branches and slow-growing short branches.

The crowns of young and mature trees are conical, while the crowns of old trees are roughly oval. Branches are nearly whorled and extend obliquely upward (the big branches of female plants are often more developed than those of male plants); One-year-old branches are light brownish yellow, two-year-old branches turn gray and have fine longitudinal cracks; Short branches are densely covered with leaves, dark gray, and long branches can also grow on short branches; Winter buds are yellowish brown, often oval, and the top is blunt and round.

Leaves alternate, scattered radially on long branches, 3-5 clusters on short branches, slender petiole, fan-shaped, light green on both sides, hairless, with many branched parallel veinlets, notched or 2-lobed wide top edge, 5-8(- 15) cm wide, and many branched veinlets. Scattered on long branches and clustered on short branches.

Its pulse type is "bifurcation pulse". On long branches, it is usually 2-lobed, with a wide base and a wedge-shaped stalk of 3- 10 cm (mostly 5-8 cm). Leaves on young trees and budding branches are often deeply split (leaf length 13 cm, width 15 cm), and sometimes the leaves split again (similar to the leaves of more primitive fossil species), and the leaves grow branches within one year.

Cones are dioecious, unisexual and clustered in the axils of scaly leaves at the top of short branches. Male cones are inflorescence-shaped, pendulous, with loose stamens and short pedicels, usually with 2 anthers, long oval, longitudinally dehiscent, and without anthers. The female cone has a long stalk, which is often divided into two branches, 3-5 or not. There is a disc-shaped ovule at the top of each fork, and the ovule is attached to it. Usually, the ovule with only one bifurcation develops into a seed and pollinates internally. When its male pollen germinates, only two ciliated swimming sperm are produced.

It blooms in April and matures in June, 5438+ 10. Seeds are long-stemmed, pendulous, often oval, obovate, ovoid or nearly spherical, 2.5-3.5 cm long and 2 cm in diameter. The aril is bony and white, and usually has 2 (sparse 3) longitudinal edges. Endosperm membranous. Seed coat is fleshy, covered with white powder, exocarp is fleshy, yellow or orange when mature, covered with white powder, and leaves have a bad smell; The middle part is white and bony with 2-3 longitudinal ridges;

Endophytic membrane, reddish brown; Endosperm is fleshy and slightly bitter; There are 2 cotyledons and 3 rare ones, which were not unearthed at the time of germination. The primary leaves are 2-5, strip-shaped, about 5 mm long and 2 mm wide, and the apex is slightly concave. After the 4th or 5th blade, the blade is fan-shaped, with a deeply divided irregular wavy notch at the top, and the petiole is 0.9-2.5cm long. There is a main root.

Extended data:

Ginkgo biloba is a light-loving tree with deep roots and wide adaptability to climate and soil. It can grow in areas with high temperature, rainy, little rainfall and cold winter, but it grows slowly or badly. It can grow on acidic soil (pH 4.5), calcareous soil (pH 8) and neutral soil, but it is not tolerant to saline-alkali and over-wet soil.

Born below the altitude of 1000 (Yunnan 1500-2000) meters, the climate is warm and humid, the annual precipitation is 700- 1500 mm, the soil layer is deep, fertile and humid, the areas with good drainage grow best, the soil is barren and dry, and the places with excessively wet rock slopes will not survive or grow badly.

Ginkgo biloba first appeared in the Carboniferous period 345 million years ago. Ginkgo biloba was widely distributed in Europe, Asia and America in the northern hemisphere, widely distributed in the northern hemisphere in Mesozoic and Jurassic, and began to decline in the late Cretaceous. By 500,000 years ago, it was extinct in most parts of Europe, North America and Asia, and only China's was preserved. Ginkgo biloba distribution mostly belongs to artificial cultivation areas, mainly cultivated in China, French and South Carolina. There is no doubt that foreign Ginkgo biloba was introduced directly or indirectly from China.

Ginkgo biloba is a rare tree species left over from Mesozoic era, and it is a specialty of China. There are only wild trees in Tianmu Mountain, Zhejiang. They are born in acidic yellow soil with good drainage at an altitude of 500- 1000 meters, and often mix with coniferous and broad-leaved trees such as Cryptomeria fortunei, Torreya grandis and Orchidaceae, and grow vigorously. Ginkgo biloba is cultivated in a wide range: from Shenyang in the northeast in the north to Guangzhou in the south, with an altitude of 40- 1000 meters in east China, and Guizhou and western Yunnan (Tengchong) with an altitude of less than 2000 meters in southwest China to produce seeds or as garden trees.

Seedlings, transplanted seedlings or tillers are often grafted in the cultivation area, which can blossom and bear fruit 8- 10 years in advance (seedlings usually start to bear seeds after 20 years). Ginkgo biloba cultivated everywhere is hundreds or thousands of years old. It is cultivated in gardens in Korea, Japan, Europe and the United States.

References:

Baidu encyclopedia-ginkgo biloba