Black-gum

Silhouette - black-gum
  • Latin name: Nyssa sylvatica Marsh.
  • French name: Nyssa sylvestre
  • Synonym(s): Sourgum , pepperidge , black tupelo
  • Taxonomic Serial Number: 27821
  • NA4 , C5
Description

Leaves

  • Leaf forms - black-gum

Form

  • Deciduous, alternate, simple
  • Shape variable
  • In clusters on dwarf branches and at the end of major shoots
  • Sparsely hairy on the veins

Length

  • 5–12 cm

Width

  • Usually widest above the middle

Colour

  • Upper surface shiny dark green
  • Lower surface whitened
  • Petiole reddish

Margin

  • Smooth, wavy

 

Buds

  • Lateral bud and leaf scar - black-gum

Form

  • Terminal bud present, curved, pointed
  • 5 scales, hairy at tips
  • Lateral buds smaller
  • Diverging widely from the twig
  • Leaf scars broadly crescent-shaped, with 3 sunken vein scars

Length

  • Terminal buds 7 mm

Colour

  • Yellowish-brown to dark reddish-brown
  • Vein scars whitish

 

Twigs

  • Longitudinal section through twig showing banded pith - black-gum
  • Winter twig - black-gum

Form

  • Moderately slender
  • Pith with hard crossbars
  • Dwarf branches present

Colour

  • Reddish-brown with a greyish skin
  • Crossbar greenish

 

Flowers

Form

  • Small, inconspicuous, on long hairy stalks
  • In small clusters, racemes or solitary
  • In the leaf axils, especially on dwarf branches

Colour

  • Greenish-white

Structure

  • Polygamo-dioecious

Floral timing

  • Late spring, after leaves reach their full size

 

Fruits

  • Fruit cluster (left); seed (right) - black-gum

Form

  • Solitary or in clusters at the ends of long stalks
  • Plum-like
  • Flesh thin, oily, sour
  • Stone indistinctly ribbed

Length

  • 1–3 cm

Colour

  • Blue-black

Structure

  • Drupe

Bark

Form

  • Flaky when young
  • Developing thick, irregular ridges broken into block-like segments

Colour

  • Grey when young, becoming dark grey

 

Wood

Texture

  • Moderately heavy, hard, strong
  • Resistant to abrasion

Colour

  • Brownish-grey

Morphology

  • Diffuse-porous, close-grained

 

Size

Height

  • To 20 m
  • Larger in the southern part of its range

Tree form

  • Silhouette - black-gum

Forest-grown

Trunk

  • Central stem distinct into the upper part of the crown

Crown

  • Broad, flat-topped, with crooked, horizontal branches

Habitat

Site

  • An understory tree on low, wet ground
  • Along streams or in swamps

Light tolerance

  • Moderately shade-tolerant

 

Range

In Ontario, north of Lake Erie

Other

Small trees. Black-gum is the only species of Nyssa native to Canada.
A variety exists that has grey twigs and thin, almost translucent leaves with many clear dots on the lower surface.

Photos
  • Black-gum
Distribution map
Distribution map - black-gum
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