The American Sycamore (Platanus occidentalis)

Peter Langballe led the Sunday walk,
while Mary Lyn Brown and Renata were two of
those who joined in.

A great way to spend a couple of hours on a Sunday afternoon is to go on one of RBG’s guided Back to Nature Walks led by an Auxiliary member.  Late fall provides different views along the trails due to the absence of foliage that normally limits how far one can see the wooded landscape.  There is still much to see, too much to describe here.  

One of several sycamore trees seen on
the trail.

One of the plants of visual  interest is the Sycamore tree (Platanus occidentalis) also known as the American sycamore, American plane tree or buttonwood, native to eastern North America. There are several of these trees along the shores of South Pasture Swamp with the large size, the bark and the fruit all catching your attention.  

The peeling bark produces the "camouflage" pattern

The bark peels off in irregular strips, leaving behind splotches of brown or gray, producing a camouflage effect.  From a distance across the swamp the towering trees stand out due to their white colour. These trees commonly inhabit wet areas. At up to fifteen feet in diameter, the sycamore develops the broadest trunk of any native tree. In fact the genus name is derived from “platy” which is Greek for “broad”.

The white sycamores are readily visible in the background.

The fruit provides great winter interest. This fruit forms brown seed balls, about one inch in diameter, which remain hanging from the tree singly attached by a long stalk.  Inside the fruit is a tightly packed cluster of “achenes” which are small, dry, one-seeded fruits that do not split at maturity, each one sporting a hairy tuft to help with dispersal, much like the dandelion. The name ‘buttonwood’ for the sycamore is due to these fruits which may stay on the tree throughout the winter, breaking apart in the wind to disperse the seeds.

The brown seed balls of the fruit.

A close up view of the seed ball.

The inside of the seed ball.

Leaf from the sycamore tree

The leaf of the tree is much like a maple leaf.  In fact Platanus acerifolia, commonly known as the London plane tree, is a hybrid resulting from the cross of Platanus occidentalis and Platanus orientalis.  It is often used in urban plantings in place of the American sycamore due to its high tolerance to pollution and its production of shade.  One way to distinguish it from the native sycamore is that the fruit balls hang in pairs. 

Note the alternate attachment
of the leaves

It has been stated that the maple leaf found on the Canadian penny is actually from this tree.  Although the sycamore leaf and maple leaf are similar, maple leaves grow ‘opposite’ on the branch while the sycamore has an ‘alternate’ arrangement.  

There is so much more information to be found about the sycamore tree.  Have a look at the following web site: http://ontariotrees.com/main/species.php?id=2083