Rock elm

Silhouette - rock elm
  • Latin name: Ulmus thomasii Sarg.
  • French name: Orme liège
  • Synonym(s): Cork elm
  • Taxonomic Serial Number: 19059
    523007 [syn. U. racemosa Thomas]
Description

Leaves

  • Leaf - rock elm

Form

  • Leathery
  • Upper surface shiny, smooth
  • Lower surface somewhat hairy
  • About 20 veins per side, rarely forked

Length

  • 5–10 cm

Colour

  • Upper surface very dark green
  • Lower surface paler

Autumn colour

  • Bright yellow

Margin

  • Teeth incurved

Buds

  • Lateral bud and leaf scar - rock elm

Form

  • Conical, sharp-pointed, plump at the base
  • Diverging from the twig
  • 3–6 vein scars per leaf scar

Length

  • 5 mm

Colour

  • Dark reddish-brown

Margin

  • Hairy

Twigs

  • Winter twig - rock elm
  • Corky ridges on 3-year-old twig; cross section (left), lateral view (right) - rock elm

Form

  • Slender, often covered with fine hairs during the 1st year, becoming smooth
  • Branchlets usually develop irregular corky ridges in the 2nd season

Colour

  • Light yellowish-brown, becoming dark reddish-brown or ash-grey

Flowers

Form

  • In clusters with a central stalk (racemes)

Structure

  • Synoecious

Fruits

  • Fruit - rock elm

Form

  • Oval, hairy
  • Wing pointed at both ends, narrow, not clearly distinct from seedcase, tip shallowly notched

Length

  • 10–15 mm

Margin

  • Noticeably hairy

Bark

Form

  • Shaggy, separated into broad, flat-topped ridges by wide, irregular, interrupted furrows
  • Surface broken into large irregular scales, often with a mottled appearance similar to white elm

Colour

  • Dark grey, tinged with red

Wood

Uses

  • Formerly in the manufacture of piano frames and hockey sticks

Size

Height

  • To 25 m

Diameter

  • To 75 cm

Maximum age

  • 175 years

Tree form

  • Silhouette - rock elm

Forest-grown

Trunk

  • Distinct almost to the top of the tree

Crown

  • Cylindrical or somewhat oval
  • Principal branches comparatively short; lower ones drooping, often crooked and gnarled, with thick ridged bark
  • General appearance rough and shaggy

Root system

  • Deep, wide-spreading

Habitat

Site

  • Most often on heavy clay soils of limestone ridges, but also on a variety of other soils

Light tolerance

  • Moderately shade-tolerant but requires full sunlight for vigorous growth
Photos
  • Rock elm
  • Rock elm
  • Rock elm
  • Rock elm
Distribution map
Distribution map - rock elm
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