Water birch

Leaves

Form

• Small, broadly oval, or widest below the middle
• Tip wedge-shaped, blunt, or sharp
• Base rounded or wedge-shaped
• Upper surface shiny
• Tiny resin dots on lower surface
• Veins 4 or 5 per side

Length

• 2–5 cm

Colour

• Upper surface deep yellowish-green
• Lower surface lighter yellowish-green

Margin

• Base has a smooth margin
• Each vein ends in a large tooth, with 3 or 4 small intervening teeth
• Teeth sharp, of 2 distinct sizes

Petiole

• Hairy

Buds

Form

• Pointed, slightly resinous

Colour

• Greenish-brown

Twigs

Form

• Very slender, often hairy

Colour

• Reddish-brown with many reddish warty resin glands

Flowers

Length

• Pollen catkins about 2 cm in winter, 6 cm at pollination
• Seed catkins about 2 cm

Structure

• Monoecious

Fruits

Form

• Mature seed catkins slender, pendulous
• Nutlet hairy
• Lateral lobes angled upward, shorter than the middle lobe

Length

• Mature seed catkins 2.5–4 cm
• On stalks 1–2 cm

Width

• Nutlet about as wide as the wings

Margin

• Scales hairy with pointed lobes

Bark

Form

• Thin, lustrous
• Not peeling readily
• Lenticels long

Colour

• Dark to nearly black when young, with age becoming purplish-brown

Size

Height

• To 12 m

Diameter

• To 30 cm

Tree form

Forest-grown

Trunk

• Leaning, crooked

Crown

• Open, with upright branches drooping at the tips

Habitat

Site

• Moist soils along streams

Associated species

• Poplars, willows, and alders
• Dense, pure thickets are common

Range

Hudson Bay to interior British Columbia