Mountain maple

Leaves

Form

• Triangular, 3–5 lobes
• Central and lateral lobes separated by wedge-shaped notches
• Lower surface hairy

Length

• 6–12 cm

Width

• Almost as wide as long

Colour

• Upper surface yellowish-green
• Lower surface white
• Petiole reddish

Autumn colour

• Red, yellow, or brown

Margin

• Coarsely and irregularly toothed
• Edges of teeth usually curved outward   

Petiole

• Slender, usually longer than leaf blade

Buds

Form

• Terminal bud present, slender
• 1 pair of visible scales that meet along their edges
• Covered with hairs

Length

• 2–3 times as long as wide

Colour

• Hairs grey

Twigs

Form

• Slender
• Coated with very short hairs
• Somewhat dull, velvety

Colour

• Yellowish-green to reddish-brown or pink 
• Hairs grey

Flowers

Form

• Stalks slender, often branched 
• 5 petals and sepals
• Arranged along a central stem in dense erect terminal clusters (panicles)

Width

• 10 mm

Colour

• Pale yellowish-green to creamy white

Structure

• Polygamo-monoecious 

Floral timing

• After the leaves are fully grown

Fruits

Form

• Incurved
• Angle between wings less than 90°
• Seedcase indented on one side
• Keys on short, sometimes branched, stalks
• Arranged around a central stem in drooping clusters
• Mature in late summer

Length

• Wings about 20 mm

Structure

• Samara
• In joined pairs

Bark

Form

• Thin, dull
• Smooth or slightly grooved

Colour

• Reddish to greyish-brown
• Often with light-coloured blotches

Size

Height

• To 5 m

Diameter

• To 15 cm

Tree form

Forest-grown

Trunk

• Short, crooked
• Irregularly divided into few ascending, slender, straight limbs

Crown

• Unevenly rounded, open

Root system

• Very shallow

Habitat

Site

• Well-drained moist soils
• Along streams, in ravines, and on moist rocky hillsides
• Common on recently cut-over northern forest land
• Often forming thickets

Light tolerance

• Shade-tolerant
• Seldom thriving in the open

Range

A characteristic understory tree of the forests of eastern Canada