Family Betulaceae – Alder, Birch & Hornbeam

Betulaceae belongs to an ancient lineage, traceable in the fossil record to the upper Cretaceous, 140 million years ago. They are easily distinguished by their woody habit; simple, pinnately veined, usually ovate, sharp-toothed leaves; long staminate catkins that often develop the season before anthesis; and (except in Corylus and Ostryopsis ) strobiluslike infructescences.

white birch

Archetypical white birch is an outstanding specimen or ornamental landscape tree

The family is held together on the basis of many features, including habit, leaf structure and arrangement, trichome morphology, wood anatomy, inflorescence morphology, ovary and ovule structure, pollen morphology, embryo structure, and fertilization and germination patterns. Five of the six constituent genera inhabit the boreal and cool temperate zones of Eurasia, North America, and the mountains of Mexico and Central America, and two genera also grow in the Andes to northern Argentina in South America. The remaining genus, Ostryopsis Decaisne (most closely related to Corylus Linnaeus), consists of two species of shrubs restricted to northern and western China.

Japanese White Birch	Dahurian Birch	European White Birch	Sweet Birch
River Birch	Paper Birch	Arctic Moor Birch	Downy / Moor Birch

Birch grows in climates ranging from boreal to humid and tolerates wide variations in precipitation. Its northern limit of growth is arctic Canada and Alaska, in boreal spruce woodlands, in mountain and sub alpine forests of the western United States, the Great Plains, and in coniferous – deciduous forests of the Northeast and Great Lakes states.

The group is sometimes divided into two families, Betulaceae ( Alnus and Betula ) and Corylaceae (Carpinus , Ostrya , Corylus , and Ostryopsis), especially in Europe. In America, this treatment has been followed by A. J. Rehder (1940), J. K. Small, and a few others.

Some of those writers have based their recognition of two families in part on the belief that a fundamental difference exists in the staminate inflorescences of the two groups. This view is no longer widely accepted, and most modern authors maintain the family as a single group composed of two subfamilies, Betuloideae and Coryloideae.” [1]

Manchurian Alder

Loose-Flowered Hornbeam

Pyramidal Black Alder

European White Alder

American Hornbeam

Alders are monoecious, that is, they have both sexes present on the same plant. Long, hanging male catkins are produced in the early winter then release pollen the following spring. Tiny female catkins appear at the shoot tips in early spring. These female catkins ripen to form green, woody conelets that after fertilization ripen into open cone-like structures called strobiles, from which the seeds are released.

American Hornbeam – Carpinus caroliniana

Arctic Moor Birch – Betula pubescens subspecies tortuosa

Asian White Birch – Betula platyphylla

Dahurian Birch – Betula davurica

Downy Birch – Betula pubescens

European Black Alder – Alnus glutinosa

European Hornbeam – Carpinus betulus

European White Alder – Alnus incana

European White Birch – Betula pendula – syn. Betula verrucosa

Family Betulaceae – Alder, Birch & Hornbeam

Japanese Hornbeam – Carpinus japonica

Japanese White Birch – Betula platyphylla var. japonica

Loose-Flowered Hornbeam – Carpinus laxiflora var. macrostachya

Manchurian Alder – Alnus hirsuta

Manchurian Birch – Betula platyphylla var. mandshurica

Manchurian Hazelnut – Corylus sieboldiana var. mandshurica

Moor Birch – Betula pubescens

Paper Birch – Betula papyrifera

Pyramidal Black Alder – Alnus glutinosa ‘Pyramidalis’

River Birch – Betula nigra

Schmidt’s Birch – Betula schmidtii

Siberian Alder – Alnus hirsuta var. sibirica

Speckled Alder – Alnus incana

Sweet Birch – Betula lenta

Turczaninov Hornbeam – Carpinus turczaninovii

White Birch Tree – Betula papyrifera

White Satin Birch – Betula ‘White Satin’

References
1. eFloras.org, Flora of North America
2. World Health Organization, Medicinal Plants in the Republic of Korea, Betula platyphylla var. japonica
3. Eun Mi Ju et al., Antioxidant and anticancer activity of extract from Betula platyphylla var. japonica

The birches have long been popular ornamental trees in North America, chiefly in the northern United States and Canada. Our specimens include river birch, Dahurian birch, paper birch, Arctic birch, Manchurian birch, Manchurian alder, downy birch, Japanese white birch, and 10 other species.
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