Betulaceae

Betulaceae, or betulaceae, is a family of the order Fagales. It is composed of deciduous and monoecious dicotyledonous trees or shrubs found in temperate regions and montane areas in the tropics. The alders and birches belong to it.

In the past, this family was divided into two, Betulaceae (Alnus and Betula) and Corylaceae (the rest); however, recent studies in the Angiosperm Phylogeny Group have led to the inclusion of the former Corylaceae family within the Betulaceae.

Description

The Betulaceae are trees and shrubs that have simple, alternate leaves with deciduous stipules. The male and female flowers are borne on the same plant, appearing before or with the leaves. Male flowers with simple perianth, in groups of 3 in the axil of a bract, arranged in hanging catkins. Female flowers without perianth, with a bicarpelar inferior gynoecium, in groups of 2 or 3 in the axil of a bract, arranged in upright catkins. The floral bracts are usually accompanied by 2 bracteoles. Anemophilous pollination. Fruits in flattened nutlets, often winged, located in a strobiliform infructescence formed by the bracts and bracteoles grown and hardened. Around 70 to 157 species divided into 6 genera (see table), most of them native to the temperate countries of the northern hemisphere.

Taxonomy

The family was described by Samuel Frederick Gray and published in A Natural Arrangement of British Plants 2: 222, 243. 1822. The type genus is: Betula L.

Genres

• Alnus - alisos
• Betula - abedules
• Carpinus - carpes
• Corylus - hazelnuts
• Ostrya - Lupulian carps
• Ostryopsis -
• Palaeocarpinus -

Uses

Many parts of plants are used in many different ways in many species, the following are just a few examples.

Many Corylus species eat the nuts raw or cooked. Cooking oil is obtained from the seeds of some Corylus species.

The bark of the Betula species in particular is used and processed in many ways.

The wood of some species is used. In general, the wood is hard, resistant and heavy, especially hornbeams; several species were of significant importance in the past when a very hard wood capable of withstanding great wear was required, as in the case of wagon wheels, water wheels, cog wheels, tool handles, planks cutting board and wooden pegs. In most of these uses, wood has been replaced by metal or other man-made materials.

The medicinal effects of some species have been studied.

Many species and their cultivars are used as ornamental plants in parks and gardens.