Identifying characteristic: Ailanthus has a bulge where the leaf stem meets the branch. It also has a pair of small gland dots on the underside at the base of every leaflet. Tree: Ailanthus possesses light brown, very smooth bark. As it gets older, the bark sometimes grows with small yellow grooves. The tree can reach a height of 80 feet (24 m.), and a diameter of 2 feet (0.6 m.).

Fruit: The fruit grows in early fall in large clusters. It is winged and has a distinctive reddish yellow color.

Location: These trees are found in many locations. On the Brandeis University campus, there is one growing next to the stairway to the Kosow-Wolfson building and many Ailanthus are also growing on the periphery of X-lot.

History and Comments: The United States Department of Agriculture, Forest Service, (http://plants.usda.gov/cgi_bin/plant_profile.cgi?symbol=AIAL) classifies Ailanthus altissima as highly invasive. It is a native of Eastern China and was introduced as an ornamental shade tree in the 1780's. Because it is impervious to city smoke and dust, it is extremely invasive in the Northeast United States and on the West coast. Its roots are slightly poisonous, sprout readily, and choke many native plants out of their forest habitat. Ailanthus will grow in almost any area, including from bricks and concrete, and it is extremely common along the sides of highways. Also, if you'd like to see a map of Ailanthus' spread in the Massachusetts, click here.