1: American Sycamore

Hi all!

I sincerely apologize for the delay! Well...it's time for our first tree! Envirothon team...meet the American Sycamore.

Common name: American Sycamore
Scientific name: Platanus occidentalis
Family: Plantanaceae

An American Sycamore on the Drillfield at Virginia Tech.

Some examples of sycamore leaves. Note the enlarged end of the petiole.

"Camouflaged" bark

The bark of the sycamore is thin, a grey-brown, and comes off easily

The green hanging "balls" are the fruits of the sycamore tree.

Another sycamore on the Drillfield.

A better example of sycamore bark.

Up close and personal with the sycamore fruit.

Sycamore twig. Notice the buds.

Another sycamore twig. Notice that at the end (look to the right), the terminal bud is absent because it is enclosed by the base of the petiole.

Form and Size: The sycamore is a large tree and will usually reach a size of 80-100 feet with a diameter of 3-4 feet. It has a large, straight trunk with branches that look spread out or "crooked". This species is well-known for having a large trunk diameter.
Habitat: Sycamores are generally found in wet areas and lowlands, and often by rivers or streams.
Leaves: The leaves are alternate, simple, and palmately veined. They have three to five lobes (separated by shallow sinuses) with toothed margins, and are usually 4-8 inches long. The bottom of the petiole is enlarged and hollow, containing the terminal bud. Leaves sometimes have fuzz or fine hairs on the underside, usually near the veins.
Flowers: The flowers are small and in clusters, with one cluster per stalk.
Fruit: The fruit is a dense ball of winged seeds that may be hard, prickly and green to soft and brown. The seeds mature in fall and disperse in winter.
Twig: The twig has a zig-zag shape, and is orange to brown-colored. Lateral buds that are on the twig are each covered by a single triangular cap.

Bark: The bark is very distinctive, being splotchy or "camouflaged". The thin brown bark comes off easily, revealing white under-bark. 

One of the things I like about tree identification is that there is always at least one distinguishing feature for each tree you meet. The top things that I would use to identify the sycamore would be its size, bark, leaves, buds, and fruits.


New vocabulary:
alternate: The leaves and buds are arranged alternately along a twig (vs. opposite).
simple: The leaf consists of one part, and is not made of multiple blades (vs. compound).
palmately veined: The veins of the leaf are arranged like the palm of a hand (vs. pinnate).
lobes: Sections of the leaf that protrude from the main part.   
margins: Outside edges of the leaf.
petiole: The stem that the leaf uses to connect to the twig.
terminal bud: The flower or leaf bud(s) found at the end of the twig.
lateral bud:The flower or leaf bud(s) found on the sides of the twig.
sinuses: dips in between the lobes of leaves.


Sources used: (I would say that 1 and 3 are the most helpful!)
1. Common Native Trees of Virginia by the Virginia Department of Forestry, 2010 Edition (Book)
2. Eastern Trees by George A. Petrides and Janet Wehr, Peterson Field Guide Series, 1998 (Book)
3. VT Dendrology: Sycamore Factsheet
4. Textbook of Dendrology by William M. Harrow, et al., 8th edition, 1996, Mc-Graw-Hill, Inc. (Book)


P.S. Sycamore flowers aren't out this time of year, so here's a picture: Sycamore Flowers