The majestic trees on the lawn below Hedrick Hall are a landmark and favorite spot to gather. Most people call these trees sycamores, but they are in fact London plane trees, Platanus x acerifolia.

These trees, while huge, were likely planted after Hedrick Hall was built in the 1930s.

Three characteristics are useful to distinguish the two similar species. One characteristic is that a London plane will sometimes have two fruit on one stem, whereas sycamore fruit are always single.

The second is that London planes will have longitudinal cracks in the stem that open in the winter. The two trees here have big sutures that are tigtly closed in the summer, open an inch or more in winter, and ooze water (xylem sap) in the spring.

A third clue is that London plane is common in the nursery trade and always planted by people. They are found along streets, in gardens, parks and campuses. American sycamore, also called buttonwood, is rarely in the nursery trade and occurs in natural habitats such as riparian forests.

London plane trees are a hybrid between American sycamore (Platanus occidentalis) and Asian sycamore (Platanus orientalis). The hybrid was made early in the British colonial era, when American plants became available to European horticulturists. The hybrid was widely planted along London streets in the 17th and 18th centuries, hence its common name.

These trees, like many London Planes, have a systemic anthracnose infection. It can be alarming to see new leaves fail to expand, which is the tyipcal symptom. Thankfully, the tree is not dying. Later leaf growth will produce a good canopy, so this disease is one the tree grows out of each season and no treatment is necessary. The severity varies considerably from year to year.