Beculaceae

1 new department of the Gemin-leaf plant,
Maya
. Deciduous trees or shrubs. Single leaves, mutual birth, leaf edge with heavy jagged or single teeth, less shallow cracking or full edge; Flower monosexual, male and female, wind media; male flower sequence spike, top or side birth, with most scales; male flowers are planted in the scaly scales, with flowers or none; males
2
to
20
, flower medicine
2
room, pollen flat spherical, with
3
or
4
to
5
holes; Flower-sequenced spruce, spiked, total or head-shaped, with most scales (called fruit when fruit), each scale has
2
to
3
female flowers; Flower beds, if there are flower beds are attached to the children's room, children's room
2
room or incomplete
2
room, flower column
2
pieces, separation, storage. Fruity wood, leather, thick paper or membrane, flat, tubular or sac-like, staying or falling off. The fruit is a firm table or small nuts. Seeds
1
, leaves flat or meaty, no endosperm. Chromosomal base
x 8
,
14
. Undergraduate is a typical department in temper belt plant department.
6
about
100
species, mainly distributed in the northern temper zone, onlywood genus distributed to Central and South America. There are
6
species
70
species in China, which are distributed all over the country, of which the tiger mule genus is endetroman of China.Wood for loose material, pale yellow-white, red-brown to brown, heart material and edge material distinction is not obvious, fine structure, planing mask gloss, cross-cutting surface pipe hole small or medium, the annual rotation boundary slightly obvious, cross-cutting water ray
1
,
2
or
3
columns, up to
4
columns, catheter molecules with trapezoidal perforation, tube perforation line is obvious, fiber pores are large, with a few small heavy-grained holes. Undergraduate plants have greater economic value, especially the birch genus is important, such as birch, black birch, brown birch, bright leaves and other important tree species and afforestation tree species in the northern tempered forest, but also one of the high-quality timber forests. In bark and other

cells containing large amounts of tannins (, anthocyanins, anthocyanins, etc.).past, birch is considered to be aflower sequence, a more primitive group of bee plants. In recent years, through the study of this kind of group flower and flower sequence morphology, it has been found that the so-called flower is actually a small cluster umbrella flower sequence, the so-called flower sequence, is actually a large umbrella-shaped conical flower sequence formed by the tightening of many small cluster flower sequence, the decline of the flower is the result of adapting to the wind media. Therefore, many scholars believe that they are not primitive groups, but special groups. The birch is closely related to The Shell, Walnut and Yang Meiko. The types and structures of their flowers and flower sequences are basically the same, and the patterns of pollen are similar. The Birch family may have occurred in the Cretaceous period, and the Third Period was widely distributed in temper zones and cold zones in the northern hemisphere. Fossils have been found in Shanwang, Shandong Province, China, and Fushun, Liaoning Province. Pollen fossils were first seen in the late Cretaceous. Since then, it has been found extensively in the formations of the Third and Fourth Periods in Eurasia. Reliable fossils of the Yi people were found in the late Neolithic period, and a large number of fossils of leaves, fruits and pollen were preserved in the third-century stratum of the northern hemisphere.the morphological structure of flowers and fruits, undergraduates are divided into
2
6
of
ethnic groups.ofmale flowers are female flowers without flowers, fruit for nuts or small nuts. There are
4
genus: (1) genus, all of which belong to more than
20,
species, distributed
in Eurasia and
North America; Shrubs or small trees; common species are hazelnuts, seeds oily
51.6
%, oily plants in northern China, nutrient-rich, edible, its nuts are common dried fruit hazelnuts. Wood is hard, fine and uniform structure, straight texture, wear resistance, a wide range of uses, but
is
cracked. (2) Tiger hazelnut genus, this genus
2
species, Chinese specialties, distributed in the north and southwest. Dwarf shrubs, commonly known as tiger hazelnuts, are one of the dominant shrubs of the loess plateau and are good soil and water-keeping tree species. Seeds contain about
10
%, edible and soapy, branches can be basketed, durable. (3) Goose-eared genus, all
40
species, distributed in the northern temper belt and north subtropical. There are about
27
15
species
in China, distributed throughout the country. Trees, wood material hard, texture dense, but fragile, can be made of farm tools or furniture. Among them, thousands of gold, short-tailed goose ears, Leigong goose ears, goose ears and Yungui goose ears, etc. are common species, especially the most widely distributed leigong goose ears. (4) Ironwood genus, all
7,
species, distributed in eastern Asia, Europe, North America to Central America, China has
4
species, produced in East China, Central China, Southwest and Shaanxi, Gansu. Among them, iron wood is more common in northern China, trees or small trees, wood material hard, pale yellow and white, shiny, can be used as furniture, agricultural tools and construction materials.birchmale flowers without flowers, female flowers with flowers; The family is
2
genus; (1) wood genus, all of which belong to more than
40,
species, distributed in Asia, Africa, Europe and North America, south to South America peru. There are


1
variants in China, which are more common in the east, north and northeast, and are also distributed in central, southwest, Shaanxi and southern Gansu. Trees or shrubs; smooth bark; wood is soft, porous, straight texture, fiber thick, perishable, low grade material, only suitable for indoor gadgets. Common are Nepaliand Jiangnanwood. (2) The genus birch belongs to about
60,
species, mainly distributed in the northern temper belt, and there are about
30


variants in China, all distributed throughout the country. Trees or shrubs, bark white, gray, red-brown or dark-brown, cracked, split, thin-layered or block-like; Poor, can be used in fine work, plywood, axle materials, sports equipment, furniture and construction, etc. , wood contains high cellulose, is a good raw material for the paper industry, bark contains tanning, can be used in the tanning industry, some can be used for daily use. This is a large amount of timber accumulation, so it has important economic value. Common are birch (
betula platyphylla
) and brown birch (
B
).
utilis
）。