Ailanthus altissima (a-lan’-thus al-tis’-i-ma)
Family: Simaroubaceae, Quassia

Key Steps

• 1b – Alternate leaf arrangement — go to 18
  • 18b – Leaf compound — go to 58
    • 58b – More than 3 leaflets — go to 59
      • 59b – Leaflet margins entire except at leaf base. Lobes on each side, like earlobes — Tree of Heaven

Description

Leaf: Oddly pinnate, 11-41 leaflets, each 3-5 inches long, not toothed except for a pair of gland-tipped teeth near leaflet base. Leaf 12-24 inches long. Smells bad when crushed. Petiole hairy.

Bud: True terminal bud absent. Lateral buds small, half round, reddish-brown, hairy, 2-4 scales showing.

Leaf Scar: Very large, triangular. Lots of bundle scars.

Stem: Stout, yellow-brown, usually hairy on young growth. Smells very bad. Whitish lenticels.

Pith: Yellow to light brown, large, continuous.

Flower: Mostly separate male and female trees. Yellow-green, 8-16 inch long panicle. Male flower smells bad. Female odorless.

Fruit: Dry, 2-winged samara, narrow, reddish-brown, one-seed in center of wing. Spirally twisted in dense clusters.

Habit: Large, upright, coarse, scraggly. Branches are stout and sparse. 50 feet tall by 40 feet wide. Fast growth rate, storm damage prone.

Culture: Very adaptable. Extremely invasive!