Betulaceae : Birch Family

Scientific Name:

Kingdom: Plantae

Divisions:

• Tracheophyta (vascular)
• Spermatophyta (seed bearing)
• Angiospermae (enclosed seeds)

Class: Dicotyledonae (two seed-leaves)

Family: Betulaceae

(Latin - Ancient name for birch probably derived from Sanskrit 'bhurga', a tree whose bark is used for writing upon. Also connected to Celtic 'betu', meaning tree.)

Genera: 2

Species: 5

Alnus crispa (Green Alder)

Alnus incana (Gray Alder)

Betula glandulosa (Dwarf Birch)

Betula occidentalis (Water Birch)

Betula papyfifera (Paper Birch)

English Name(s):

Birch Family

Description:

• Plants monoecious, woody, shrubs or trees
• Leaves simple, alternate, deciduous, toothed.
• Flowers imperfect (one-gendered) in catkins.
• Fruit is a small single seeded nutlet.

Natural History:

• Rely on wind for both pollination and seed dispersal.

Family Size:

World:

Genera: 6

Species: 150

North America:

Genera: 5

Species:

Yukon:

Genera: 2

Species: 6-9 (depending on taxonomy used)

Alnus (Alder)

• Shrubs or small trees
• Bark reddish or greyish brown
• Female catkins woody and persistent
• Stamens 4

World= 30

N.A.= ?

Yukon= 2-3 (depending on taxonomy used)

Betula (Birch)

• Shrubs or trees
• Branchlets often dotted with wart-like glands
• Female catkins deciduous
• All our species can and do hybridize.

World= 40

N.A.= ?

Yukon= 4-6 (depending on taxonomy used)

Central Yukon= 3